aboutsummaryrefslogtreecommitdiff
path: root/el_GR.ISO8859-7/books/handbook/disks/chapter.xml
blob: 987380c80cefd85fea30ed36b762527712d6cdc2 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
2269
2270
2271
2272
2273
2274
2275
2276
2277
2278
2279
2280
2281
2282
2283
2284
2285
2286
2287
2288
2289
2290
2291
2292
2293
2294
2295
2296
2297
2298
2299
2300
2301
2302
2303
2304
2305
2306
2307
2308
2309
2310
2311
2312
2313
2314
2315
2316
2317
2318
2319
2320
2321
2322
2323
2324
2325
2326
2327
2328
2329
2330
2331
2332
2333
2334
2335
2336
2337
2338
2339
2340
2341
2342
2343
2344
2345
2346
2347
2348
2349
2350
2351
2352
2353
2354
2355
2356
2357
2358
2359
2360
2361
2362
2363
2364
2365
2366
2367
2368
2369
2370
2371
2372
2373
2374
2375
2376
2377
2378
2379
2380
2381
2382
2383
2384
2385
2386
2387
2388
2389
2390
2391
2392
2393
2394
2395
2396
2397
2398
2399
2400
2401
2402
2403
2404
2405
2406
2407
2408
2409
2410
2411
2412
2413
2414
2415
2416
2417
2418
2419
2420
2421
2422
2423
2424
2425
2426
2427
2428
2429
2430
2431
2432
2433
2434
2435
2436
2437
2438
2439
2440
2441
2442
2443
2444
2445
2446
2447
2448
2449
2450
2451
2452
2453
2454
2455
2456
2457
2458
2459
2460
2461
2462
2463
2464
2465
2466
2467
2468
2469
2470
2471
2472
2473
2474
2475
2476
2477
2478
2479
2480
2481
2482
2483
2484
2485
2486
2487
2488
2489
2490
2491
2492
2493
2494
2495
2496
2497
2498
2499
2500
2501
2502
2503
2504
2505
2506
2507
2508
2509
2510
2511
2512
2513
2514
2515
2516
2517
2518
2519
2520
2521
2522
2523
2524
2525
2526
2527
2528
2529
2530
2531
2532
2533
2534
2535
2536
2537
2538
2539
2540
2541
2542
2543
2544
2545
2546
2547
2548
2549
2550
2551
2552
2553
2554
2555
2556
2557
2558
2559
2560
2561
2562
2563
2564
2565
2566
2567
2568
2569
2570
2571
2572
2573
2574
2575
2576
2577
2578
2579
2580
2581
2582
2583
2584
2585
2586
2587
2588
2589
2590
2591
2592
2593
2594
2595
2596
2597
2598
2599
2600
2601
2602
2603
2604
2605
2606
2607
2608
2609
2610
2611
2612
2613
2614
2615
2616
2617
2618
2619
2620
2621
2622
2623
2624
2625
2626
2627
2628
2629
2630
2631
2632
2633
2634
2635
2636
2637
2638
2639
2640
2641
2642
2643
2644
2645
2646
2647
2648
2649
2650
2651
2652
2653
2654
2655
2656
2657
2658
2659
2660
2661
2662
2663
2664
2665
2666
2667
2668
2669
2670
2671
2672
2673
2674
2675
2676
2677
2678
2679
2680
2681
2682
2683
2684
2685
2686
2687
2688
2689
2690
2691
2692
2693
2694
2695
2696
2697
2698
2699
2700
2701
2702
2703
2704
2705
2706
2707
2708
2709
2710
2711
2712
2713
2714
2715
2716
2717
2718
2719
2720
2721
2722
2723
2724
2725
2726
2727
2728
2729
2730
2731
2732
2733
2734
2735
2736
2737
2738
2739
2740
2741
2742
2743
2744
2745
2746
2747
2748
2749
2750
2751
2752
2753
2754
2755
2756
2757
2758
2759
2760
2761
2762
2763
2764
2765
2766
2767
2768
2769
2770
2771
2772
2773
2774
2775
2776
2777
2778
2779
2780
2781
2782
2783
2784
2785
2786
2787
2788
2789
2790
2791
2792
2793
2794
2795
2796
2797
2798
2799
2800
2801
2802
2803
2804
2805
2806
2807
2808
2809
2810
2811
2812
2813
2814
2815
2816
2817
2818
2819
2820
2821
2822
2823
2824
2825
2826
2827
2828
2829
2830
2831
2832
2833
2834
2835
2836
2837
2838
2839
2840
2841
2842
2843
2844
2845
2846
2847
2848
2849
2850
2851
2852
2853
2854
2855
2856
2857
2858
2859
2860
2861
2862
2863
2864
2865
2866
2867
2868
2869
2870
2871
2872
2873
2874
2875
2876
2877
2878
2879
2880
2881
2882
2883
2884
2885
2886
2887
2888
2889
2890
2891
2892
2893
2894
2895
2896
2897
2898
2899
2900
2901
2902
2903
2904
2905
2906
2907
2908
2909
2910
2911
2912
2913
2914
2915
2916
2917
2918
2919
2920
2921
2922
2923
2924
2925
2926
2927
2928
2929
2930
2931
2932
2933
2934
2935
2936
2937
2938
2939
2940
2941
2942
2943
2944
2945
2946
2947
2948
2949
2950
2951
2952
2953
2954
2955
2956
2957
2958
2959
2960
2961
2962
2963
2964
2965
2966
2967
2968
2969
2970
2971
2972
2973
2974
2975
2976
2977
2978
2979
2980
2981
2982
2983
2984
2985
2986
2987
2988
2989
2990
2991
2992
2993
2994
2995
2996
2997
2998
2999
3000
3001
3002
3003
3004
3005
3006
3007
3008
3009
3010
3011
3012
3013
3014
3015
3016
3017
3018
3019
3020
3021
3022
3023
3024
3025
3026
3027
3028
3029
3030
3031
3032
3033
3034
3035
3036
3037
3038
3039
3040
3041
3042
3043
3044
3045
3046
3047
3048
3049
3050
3051
3052
3053
3054
3055
3056
3057
3058
3059
3060
3061
3062
3063
3064
3065
3066
3067
3068
3069
3070
3071
3072
3073
3074
3075
3076
3077
3078
3079
3080
3081
3082
3083
3084
3085
3086
3087
3088
3089
3090
3091
3092
3093
3094
3095
3096
3097
3098
3099
3100
3101
3102
3103
3104
3105
3106
3107
3108
3109
3110
3111
3112
3113
3114
3115
3116
3117
3118
3119
3120
3121
3122
3123
3124
3125
3126
3127
3128
3129
3130
3131
3132
3133
3134
3135
3136
3137
3138
3139
3140
3141
3142
3143
3144
3145
3146
3147
3148
3149
3150
3151
3152
3153
3154
3155
3156
3157
3158
3159
3160
3161
3162
3163
3164
3165
3166
3167
3168
3169
3170
3171
3172
3173
3174
3175
3176
3177
3178
3179
3180
3181
3182
3183
3184
3185
3186
3187
3188
3189
3190
3191
3192
3193
3194
3195
3196
3197
3198
3199
3200
3201
3202
3203
3204
3205
3206
3207
3208
3209
3210
3211
3212
3213
3214
3215
3216
3217
3218
3219
3220
3221
3222
3223
3224
3225
3226
3227
3228
3229
3230
3231
3232
3233
3234
3235
3236
3237
3238
3239
3240
3241
3242
3243
3244
3245
3246
3247
3248
3249
3250
3251
3252
3253
3254
3255
3256
3257
3258
3259
3260
3261
3262
3263
3264
3265
3266
3267
3268
3269
3270
3271
3272
3273
3274
3275
3276
3277
3278
3279
3280
3281
3282
3283
3284
3285
3286
3287
3288
3289
3290
3291
3292
3293
3294
3295
3296
3297
3298
3299
3300
3301
3302
3303
3304
3305
3306
3307
3308
3309
3310
3311
3312
3313
3314
3315
3316
3317
3318
3319
3320
3321
3322
3323
3324
3325
3326
3327
3328
3329
3330
3331
3332
3333
3334
3335
3336
3337
3338
3339
3340
3341
3342
3343
3344
3345
3346
3347
3348
3349
3350
3351
3352
3353
3354
3355
3356
3357
3358
3359
3360
3361
3362
3363
3364
3365
3366
3367
3368
3369
3370
3371
3372
3373
3374
3375
3376
3377
3378
3379
3380
3381
3382
3383
3384
3385
3386
3387
3388
3389
3390
3391
3392
3393
3394
3395
3396
3397
3398
3399
3400
3401
3402
3403
3404
3405
3406
3407
3408
3409
3410
3411
3412
3413
3414
3415
3416
3417
3418
3419
3420
3421
3422
3423
3424
3425
3426
3427
3428
3429
3430
3431
3432
3433
3434
3435
3436
3437
3438
3439
3440
3441
3442
3443
3444
3445
3446
3447
3448
3449
3450
3451
3452
3453
3454
3455
3456
3457
3458
3459
3460
3461
3462
3463
3464
3465
3466
3467
3468
3469
3470
3471
3472
3473
3474
3475
3476
3477
3478
3479
3480
3481
3482
3483
3484
3485
3486
3487
3488
3489
3490
3491
3492
3493
3494
3495
3496
3497
3498
3499
3500
3501
3502
3503
3504
3505
3506
3507
3508
3509
3510
3511
3512
3513
3514
3515
3516
3517
3518
3519
3520
3521
3522
3523
3524
3525
3526
3527
3528
3529
3530
3531
3532
3533
3534
3535
3536
3537
3538
3539
3540
3541
3542
3543
3544
3545
3546
3547
3548
3549
3550
3551
3552
3553
3554
3555
3556
3557
3558
3559
3560
3561
3562
3563
3564
3565
3566
3567
3568
3569
3570
3571
3572
3573
3574
3575
3576
3577
3578
3579
3580
3581
3582
3583
3584
3585
3586
3587
3588
3589
3590
3591
3592
3593
3594
3595
3596
3597
3598
3599
3600
3601
3602
3603
3604
3605
3606
3607
3608
3609
3610
3611
3612
3613
3614
3615
3616
3617
3618
3619
3620
3621
3622
3623
3624
3625
3626
3627
3628
3629
3630
3631
3632
3633
3634
3635
3636
3637
3638
3639
3640
3641
3642
3643
3644
3645
3646
3647
3648
3649
3650
3651
3652
3653
3654
3655
3656
3657
3658
3659
3660
3661
3662
3663
3664
3665
3666
3667
3668
3669
3670
3671
3672
3673
3674
3675
3676
3677
3678
3679
3680
3681
3682
3683
3684
3685
3686
3687
3688
3689
3690
3691
3692
3693
3694
3695
3696
3697
3698
3699
3700
3701
3702
3703
3704
3705
3706
3707
3708
3709
3710
3711
3712
3713
3714
3715
3716
3717
3718
3719
3720
3721
3722
3723
3724
3725
3726
3727
3728
3729
3730
3731
3732
3733
3734
3735
3736
3737
3738
3739
3740
3741
3742
3743
3744
3745
3746
3747
3748
3749
3750
3751
3752
3753
3754
3755
3756
3757
3758
3759
3760
3761
3762
3763
3764
3765
3766
3767
3768
3769
3770
3771
3772
3773
3774
3775
3776
3777
3778
3779
3780
3781
3782
3783
3784
3785
3786
3787
3788
3789
3790
3791
3792
3793
3794
3795
3796
3797
3798
3799
3800
3801
3802
3803
3804
3805
3806
3807
3808
3809
3810
3811
3812
3813
3814
3815
3816
3817
3818
3819
3820
3821
3822
3823
3824
3825
3826
3827
3828
3829
3830
3831
3832
3833
3834
3835
3836
3837
3838
3839
3840
3841
3842
3843
3844
3845
3846
3847
3848
3849
3850
3851
3852
3853
3854
3855
3856
3857
3858
3859
3860
3861
3862
3863
3864
3865
3866
3867
3868
3869
3870
3871
3872
3873
3874
3875
3876
3877
3878
3879
3880
3881
3882
3883
3884
3885
3886
3887
3888
3889
3890
3891
3892
3893
3894
3895
3896
3897
3898
3899
3900
3901
3902
3903
3904
3905
3906
3907
3908
3909
3910
3911
3912
3913
3914
3915
3916
3917
3918
3919
3920
3921
3922
3923
3924
3925
3926
3927
3928
3929
3930
3931
3932
3933
3934
3935
3936
3937
3938
3939
3940
3941
3942
3943
3944
3945
3946
3947
3948
3949
3950
3951
3952
3953
3954
3955
3956
3957
3958
3959
3960
3961
3962
3963
3964
3965
3966
3967
3968
3969
3970
3971
3972
3973
3974
3975
3976
3977
3978
3979
3980
3981
3982
3983
3984
3985
3986
3987
3988
3989
3990
3991
3992
3993
3994
3995
3996
3997
3998
3999
4000
4001
4002
4003
4004
4005
4006
4007
4008
4009
4010
4011
4012
4013
4014
4015
4016
4017
4018
4019
4020
4021
4022
4023
4024
4025
4026
4027
4028
4029
4030
4031
4032
4033
4034
4035
4036
4037
4038
4039
4040
4041
4042
4043
4044
4045
4046
4047
4048
4049
4050
4051
4052
<?xml version="1.0" encoding="iso-8859-7"?>
<!--

     FreeBSD:  

  The FreeBSD Greek Documentation Project

  $FreeBSD$

  %SOURCE%	en_US.ISO8859-1/books/handbook/disks/chapter.xml
  %SRCID%	1.1

-->
<chapter xmlns="http://docbook.org/ns/docbook" xmlns:xlink="http://www.w3.org/1999/xlink" version="5.0" xml:id="disks">
  <title> </title>

  <sect1 xml:id="disks-synopsis">
    <title></title>


    <para>         &os;.
           ,  
        ,     SCSI/IDE, 
           USB.</para>

    <para>    ,  :</para>
    <itemizedlist>
      <listitem><para>     &os;   
               
       (partitions -  -   slices).</para>
      </listitem>

      <listitem><para>      
         .</para>
      </listitem>
      <listitem>
	<para>    &os;   
           USB.</para>
      </listitem>
      <listitem><para>     , 
            RAM.</para></listitem>
      <listitem>
	<para>   quotas     
            .</para>
      </listitem>
      <listitem>
	<para>       
           .</para>
      </listitem>
      <listitem>
	<para>      CD  DVD
           &os;.</para>
      </listitem>
      <listitem>
        <para>      
          .</para>
      </listitem>
      <listitem>
        <para>     
            &os;.</para>
      </listitem>
      <listitem>
        <para>      .</para>
      </listitem>
      <listitem>
        <para>    (snapshots)      
             .</para>
      </listitem>
    </itemizedlist>

    <para>    ,  :</para>

    <itemizedlist>
      <listitem>
        <para>          
            &os; (<xref linkend="kernelconfig"/>).</para>
      </listitem>
    </itemizedlist>

  </sect1>

  <sect1 xml:id="disks-naming">
    <title>Device Names</title>

    <para>The following is a list of physical storage devices
      supported in FreeBSD, and the device names associated with
      them.</para>

    <table xml:id="disk-naming-physical-table" frame="none">
      <title>Physical Disk Naming Conventions</title>

      <tgroup cols="2">
	<thead>
	  <row>
	    <entry>Drive type</entry>
	    <entry>Drive device name</entry>
	  </row>
	</thead>
	<tbody>
	  <row>
	    <entry>IDE hard drives</entry>
	    <entry><literal>ad</literal></entry>
	  </row>
	  <row>
	    <entry>IDE CDROM drives</entry>
	    <entry><literal>acd</literal></entry>
	  </row>
	  <row>
	    <entry>SCSI hard drives and USB Mass storage devices</entry>
	    <entry><literal>da</literal></entry>
	  </row>
	  <row>
	    <entry>SCSI CDROM drives</entry>
	    <entry><literal>cd</literal></entry>
	  </row>
	  <row>
	    <entry>Assorted non-standard CDROM drives</entry>
	    <entry><literal>mcd</literal> for Mitsumi CD-ROM and
	      <literal>scd</literal> for Sony CD-ROM devices
	    </entry>
	  </row>
	  <row>
	    <entry>Floppy drives</entry>
	    <entry><literal>fd</literal></entry>
	  </row>
	  <row>
	    <entry>SCSI tape drives</entry>
	    <entry><literal>sa</literal></entry>
            </row>
	  <row>
	    <entry>IDE tape drives</entry>
	    <entry><literal>ast</literal></entry>
	  </row>
	  <row>
	    <entry>Flash drives</entry>
	    <entry><literal>fla</literal> for &diskonchip; Flash device</entry>
	  </row>
	  <row>
	    <entry>RAID drives</entry>
	    <entry><literal>aacd</literal> for &adaptec; AdvancedRAID,
	      <literal>mlxd</literal> and <literal>mlyd</literal>
	      for &mylex;,
	      <literal>amrd</literal> for AMI &megaraid;,
	      <literal>idad</literal> for Compaq Smart RAID,
	      <literal>twed</literal> for &tm.3ware; RAID.</entry>
	  </row>
	</tbody>
      </tgroup>
    </table>
  </sect1>

  <sect1 xml:id="disks-adding">
    <info><title>Adding Disks</title>
      <authorgroup>
	<author><personname><firstname>David</firstname><surname>O'Brien</surname></personname><contrib>Originally contributed by </contrib></author>
      </authorgroup>
      
    </info>

    

    <indexterm>
      <primary>disks</primary>
      <secondary>adding</secondary>
    </indexterm>

    <para>Lets say we want to add a new SCSI disk to a machine that
      currently only has a single drive.  First turn off the computer
      and install the drive in the computer following the instructions
      of the computer, controller, and drive manufacturer.  Due to the
      wide variations of procedures to do this, the details are beyond
      the scope of this document.</para>

    <para>Login as user <systemitem class="username">root</systemitem>.  After you have installed the
      drive, inspect <filename>/var/run/dmesg.boot</filename> to ensure the new
      disk was found.  Continuing with our example, the newly added drive will
      be <filename>da1</filename> and we want to mount it on
      <filename>/1</filename> (if you are adding an IDE drive, the device name
      will be <filename>ad1</filename>).</para>

    <indexterm><primary>partitions</primary></indexterm>
    <indexterm><primary>slices</primary></indexterm>
    <indexterm>
      <primary><command>fdisk</command></primary>
    </indexterm>

    <para>FreeBSD runs on IBM-PC compatible computers, therefore it must
      take into account the PC BIOS partitions.  These are different
      from the traditional BSD partitions.  A PC disk has up to four
      BIOS partition entries.  If the disk is going to be truly
      dedicated to FreeBSD, you can use the
      <emphasis>dedicated</emphasis> mode.  Otherwise, FreeBSD will
      have to live within one of the PC BIOS partitions.  FreeBSD
      calls the PC BIOS partitions <emphasis>slices</emphasis> so as
      not to confuse them with traditional BSD partitions.  You may
      also use slices on a disk that is dedicated to FreeBSD, but used
      in a computer that also has another operating system installed.
      This is a good way to avoid confusing the <command>fdisk</command> utility of
      other, non-FreeBSD operating systems.</para>

    <para>In the slice case the drive will be added as
      <filename>/dev/da1s1e</filename>.  This is read as: SCSI disk,
      unit number 1 (second SCSI disk), slice 1 (PC BIOS partition 1),
      and <filename>e</filename> BSD partition.  In the dedicated
      case, the drive will be added simply as
      <filename>/dev/da1e</filename>.</para>

    <para>Due to the use of 32-bit integers to store the number of sectors,
      &man.bsdlabel.8; is
      limited to 2^32-1 sectors per disk or 2TB in most cases.  The
      &man.fdisk.8; format allows a starting sector of no more than
      2^32-1 and a length of no more than 2^32-1, limiting partitions to
      2TB and disks to 4TB in most cases.  The &man.sunlabel.8; format
      is limited to 2^32-1 sectors per partition and 8 partitions for
      a total of 16TB. For larger disks, &man.gpt.8; partitions may be
      used.</para>

    <sect2>
      <title>Using &man.sysinstall.8;</title>
      <indexterm>
        <primary><application>sysinstall</application></primary>
        <secondary>adding disks</secondary>
      </indexterm>
      <indexterm>
	<primary>su</primary>
      </indexterm>
      <procedure>
	<step>
	  <title>Navigating <application>Sysinstall</application></title>

	  <para>You may use <command>sysinstall</command> to
	    partition and label a new disk using its easy to use menus.
	    Either login as user <systemitem class="username">root</systemitem> or use the
	    <command>su</command> command.  Run
	    <command>sysinstall</command> and enter the
	    <literal>Configure</literal> menu.  Within the
	    <literal>FreeBSD Configuration Menu</literal>, scroll down and
	    select the <literal>Fdisk</literal> option.</para>
	</step>

	<step>
	  <title><application>fdisk</application> Partition Editor</title>
	  <para>Once inside <application>fdisk</application>, typing <userinput>A</userinput> will
	    use the entire disk for FreeBSD.  When asked if you want to
	    <quote>remain cooperative with any future possible operating
	      systems</quote>, answer <literal>YES</literal>.  Write the
	    changes to the disk using <userinput>W</userinput>.  Now exit the
	    FDISK editor by typing <userinput>q</userinput>.  Next you will be
	    asked about the <quote>Master Boot Record</quote>.  Since you are adding a
	    disk to an already running system, choose
	    <literal>None</literal>.</para>
	</step>

	<step>
	  <title>Disk Label Editor</title>
	  <indexterm><primary>BSD partitions</primary></indexterm>

	  <para>Next, you need to exit <application>sysinstall</application>
            and start it again.  Follow the directions above, although this
            time choose the <literal>Label</literal> option. This will
	    enter the <literal>Disk Label Editor</literal>.  This
	    is where you will create the traditional BSD partitions.  A
	    disk can have up to eight partitions, labeled
	    <literal>a-h</literal>.
	    A few of the partition labels have special uses.  The
	    <literal>a</literal> partition is used for the root partition
	    (<filename>/</filename>).  Thus only your system disk (e.g,
	    the disk you boot from) should have an <literal>a</literal>
	    partition.  The <literal>b</literal> partition is used for
	    swap partitions, and you may have many disks with swap
	    partitions.  The <literal>c</literal> partition addresses the
	    entire disk in dedicated mode, or the entire FreeBSD slice in
	    slice mode.  The other partitions are for general use.</para>

	  <para><application>sysinstall</application>'s Label editor
	    favors the <literal>e</literal>
	    partition for non-root, non-swap partitions.  Within the
	    Label editor, create a single file system by typing
	    <userinput>C</userinput>.  When prompted if this will be a FS
	    (file system) or swap, choose <literal>FS</literal> and type in a
	    mount point (e.g, <filename>/mnt</filename>).  When adding a
	    disk in post-install mode, <application>sysinstall</application>
	    will not create entries
	    in <filename>/etc/fstab</filename> for you, so the mount point
	    you specify is not important.</para>

	  <para>You are now ready to write the new label to the disk and
	    create a file system on it.  Do this by typing
	    <userinput>W</userinput>.  Ignore any errors from
	    <application>sysinstall</application> that
	    it could not mount the new partition.  Exit the Label Editor
	    and <application>sysinstall</application> completely.</para>
	</step>

	<step>
	  <title>Finish</title>

	  <para>The last step is to edit <filename>/etc/fstab</filename>
	    to add an entry for your new disk.</para>
	</step>
      </procedure>
    </sect2>

    <sect2>
      <title>Using Command Line Utilities</title>

      <sect3>
	<title>Using Slices</title>

	<para>This setup will allow your disk to work correctly with
	  other operating systems that might be installed on your
	  computer and will not confuse other operating systems'
	  <command>fdisk</command> utilities.  It is recommended
	  to use this method for new disk installs.  Only use
	  <literal>dedicated</literal> mode if you have a good reason
	  to do so!</para>

	<screen>&prompt.root; <userinput>dd if=/dev/zero of=/dev/da1 bs=1k count=1</userinput>
&prompt.root; <userinput>fdisk -BI da1</userinput> #Initialize your new disk
&prompt.root; <userinput>bsdlabel -B -w -r da1s1 auto</userinput> #Label it.
&prompt.root; <userinput>bsdlabel -e da1s1</userinput> # Edit the bsdlabel just created and add any partitions.
&prompt.root; <userinput>mkdir -p /1</userinput>
&prompt.root; <userinput>newfs /dev/da1s1e</userinput> # Repeat this for every partition you created.
&prompt.root; <userinput>mount /dev/da1s1e /1</userinput> # Mount the partition(s)
&prompt.root; <userinput>vi /etc/fstab</userinput> # Add the appropriate entry/entries to your <filename>/etc/fstab</filename>.</screen>

	<para>If you have an IDE disk, substitute <filename>ad</filename>
	  for <filename>da</filename>.</para>
      </sect3>

      <sect3>
	<title>Dedicated</title>
	<indexterm><primary>OS/2</primary></indexterm>

	<para>If you will not be sharing the new drive with another operating
	  system, you may use the <literal>dedicated</literal> mode.  Remember
	  this mode can confuse Microsoft operating systems; however, no damage
	  will be done by them.  IBM's &os2; however, will
	  <quote>appropriate</quote> any partition it finds which it does not
	  understand.</para>

	<screen>&prompt.root; <userinput>dd if=/dev/zero of=/dev/da1 bs=1k count=1</userinput>
&prompt.root; <userinput>bsdlabel -Brw da1 auto</userinput>
&prompt.root; <userinput>bsdlabel -e da1</userinput>				# create the `e' partition
&prompt.root; <userinput>newfs -d0 /dev/da1e</userinput>
&prompt.root; <userinput>mkdir -p /1</userinput>
&prompt.root; <userinput>vi /etc/fstab</userinput>				# add an entry for /dev/da1e
&prompt.root; <userinput>mount /1</userinput></screen>

	<para>An alternate method is:</para>

	<screen>&prompt.root; <userinput>dd if=/dev/zero of=/dev/da1 count=2</userinput>
&prompt.root; <userinput>bsdlabel /dev/da1 | bsdlabel -BrR da1 /dev/stdin</userinput>
&prompt.root; <userinput>newfs /dev/da1e</userinput>
&prompt.root; <userinput>mkdir -p /1</userinput>
&prompt.root; <userinput>vi /etc/fstab</userinput>					# add an entry for /dev/da1e
&prompt.root; <userinput>mount /1</userinput></screen>

      </sect3>
    </sect2>
  </sect1>

  <sect1 xml:id="raid">
    <title>RAID</title>

    <sect2 xml:id="raid-soft">
      <title>Software RAID</title>

      <sect3 xml:id="ccd">
	<info><title>Concatenated Disk Driver (CCD) Configuration</title>
	  <authorgroup>
	    <author><personname><firstname>Christopher</firstname><surname>Shumway</surname></personname><contrib>Original work by </contrib></author>
	  </authorgroup>
	  <authorgroup>
	    <author><personname><firstname>Jim</firstname><surname>Brown</surname></personname><contrib>Revised by </contrib></author>
	  </authorgroup>
	</info>

	

<indexterm><primary>RAID</primary><secondary>software</secondary></indexterm>
<indexterm>
  <primary>RAID</primary><secondary>CCD</secondary>
</indexterm>

	<para>When choosing a mass storage solution the most important
	  factors to consider are speed, reliability, and cost.  It is
	  rare to have all three in balance; normally a fast, reliable mass
	  storage device is expensive, and to cut back on cost either speed
	  or reliability must be sacrificed.</para>

          <para>In designing the system described below, cost was chosen
          as  the most important factor, followed by speed, then reliability.
          Data transfer speed for this system is ultimately
          constrained by the network.  And while reliability is very important,
          the CCD drive described below serves online data that is already
          fully backed up on CD-R's and can easily be replaced.</para>

          <para>Defining your own requirements is the first step
          in choosing a mass storage solution.  If your requirements prefer
          speed or reliability over cost, your solution will differ from
          the system described in this section.</para>


	<sect4 xml:id="ccd-installhw">
	  <title>Installing the Hardware</title>

	  <para>In addition to the IDE system disk, three Western
            Digital 30GB, 5400 RPM IDE disks form the core
            of the CCD disk described below providing approximately
	    90GB of online storage.  Ideally,
	    each IDE disk would have its own IDE controller
	    and cable, but to minimize cost, additional
	    IDE controllers were not used.  Instead the disks were
	    configured with jumpers so that each IDE controller has
            one master, and one slave.</para>

	  <para>Upon reboot, the system BIOS was configured to
	    automatically detect the disks attached.  More importantly,
	    FreeBSD detected them on reboot:</para>

	  <programlisting>ad0: 19574MB &lt;WDC WD205BA&gt; [39770/16/63] at ata0-master UDMA33
ad1: 29333MB &lt;WDC WD307AA&gt; [59598/16/63] at ata0-slave UDMA33
ad2: 29333MB &lt;WDC WD307AA&gt; [59598/16/63] at ata1-master UDMA33
ad3: 29333MB &lt;WDC WD307AA&gt; [59598/16/63] at ata1-slave UDMA33</programlisting>

 	  <note><para>If FreeBSD does not detect all the disks, ensure
 	    that you have jumpered them correctly.  Most IDE drives
 	    also have a <quote>Cable Select</quote> jumper.  This is
 	    <emphasis>not</emphasis> the jumper for the master/slave
 	    relationship.  Consult the drive documentation for help in
 	    identifying the correct jumper.</para></note>

 	  <para>Next, consider how to attach them as part of the file
 	    system.  You should research both &man.vinum.8; (<xref linkend="vinum-vinum"/>) and &man.ccd.4;.  In this
 	    particular configuration, &man.ccd.4; was chosen.</para>
	</sect4>

	<sect4 xml:id="ccd-setup">
	  <title>Setting Up the CCD</title>

 	  <para>The &man.ccd.4; driver allows you to take
  	    several identical disks and concatenate them into one
  	    logical file system.  In order to use
 	    &man.ccd.4;, you need a kernel with
 	    &man.ccd.4; support built in.
 	    Add this line to your kernel configuration file, rebuild, and
 	    reinstall the kernel:</para>

	  <programlisting>device   ccd</programlisting>

	  <para>The &man.ccd.4; support can also be
	    loaded as a kernel loadable module.</para>

 	  <para>To set up &man.ccd.4;, you must first use
 	    &man.bsdlabel.8; to label the disks:</para>

	  <programlisting>bsdlabel -r -w ad1 auto
bsdlabel -r -w ad2 auto
bsdlabel -r -w ad3 auto</programlisting>

 	  <para>This creates a bsdlabel for <filename>ad1c</filename>, <filename>ad2c</filename> and <filename>ad3c</filename> that
  	    spans the entire disk.</para>

 	  <para>The next step is to change the disk label type.  You
 	    can use &man.bsdlabel.8; to edit the
 	    disks:</para>

	  <programlisting>bsdlabel -e ad1
bsdlabel -e ad2
bsdlabel -e ad3</programlisting>

 	  <para>This opens up the current disk label on each disk with
 	    the editor specified by the <envar>EDITOR</envar>
 	    environment variable, typically &man.vi.1;.</para>

	  <para>An unmodified disk label will look something like
	    this:</para>

	  <programlisting>8 partitions:
#        size   offset    fstype   [fsize bsize bps/cpg]
  c: 60074784        0    unused        0     0     0   # (Cyl.    0 - 59597)</programlisting>

 	  <para>Add a new <literal>e</literal> partition for &man.ccd.4; to use. This
 	    can usually be copied from the <literal>c</literal> partition,
 	    but the <option>fstype</option> <emphasis>must</emphasis>
 	    be <userinput>4.2BSD</userinput>.  The disk label should
 	    now look something like this:</para>

	  <programlisting>8 partitions:
#        size   offset    fstype   [fsize bsize bps/cpg]
  c: 60074784        0    unused        0     0     0   # (Cyl.    0 - 59597)
  e: 60074784        0    4.2BSD        0     0     0   # (Cyl.    0 - 59597)</programlisting>

	</sect4>

	<sect4 xml:id="ccd-buildingfs">
	  <title>Building the File System</title>

	  <para>Now that you have all the disks labeled, you must
	    build the &man.ccd.4;.  To do that,
	    use  &man.ccdconfig.8;, with options similar to the following:</para>

	    <programlisting>ccdconfig ccd0<co xml:id="co-ccd-dev"/> 32<co xml:id="co-ccd-interleave"/> 0<co xml:id="co-ccd-flags"/> /dev/ad1e<co xml:id="co-ccd-devs"/> /dev/ad2e /dev/ad3e</programlisting>

	  <para>The use and meaning of each option is shown below:</para>

          <calloutlist>
            <callout arearefs="co-ccd-dev">
	    <para>The first argument is the device to configure, in this case,
	    <filename>/dev/ccd0c</filename>. The <filename>/dev/</filename>
            portion is optional.</para>
            </callout>

            <callout arearefs="co-ccd-interleave">

	    <para>The interleave for the file system.  The interleave
	    defines the size of a stripe in disk blocks, each normally 512 bytes.
	    So, an interleave of 32 would be 16,384 bytes.</para>
            </callout>

            <callout arearefs="co-ccd-flags">
	    <para>Flags for &man.ccdconfig.8;.  If you want to enable drive
	    mirroring, you can specify a flag here. This
	    configuration does not provide mirroring for
	    &man.ccd.4;, so it is set at 0 (zero).</para>
            </callout>

            <callout arearefs="co-ccd-devs">
	    <para>The final arguments to &man.ccdconfig.8;
	    are the devices to place into the array.  Use the complete pathname
	    for each device.</para>
            </callout>
          </calloutlist>


	  <para>After running &man.ccdconfig.8; the &man.ccd.4;
          is configured. A file system can be installed. Refer to &man.newfs.8;
          for options, or simply run: </para>

	  <programlisting>newfs /dev/ccd0c</programlisting>


	</sect4>

	<sect4 xml:id="ccd-auto">
	  <title>Making it All Automatic</title>

	  <para>Generally, you will want to mount the
	    &man.ccd.4; upon each reboot. To do this, you must
	    configure it first.  Write out your current configuration to
	    <filename>/etc/ccd.conf</filename> using the following command:</para>

	  <programlisting>ccdconfig -g &gt; /etc/ccd.conf</programlisting>

	  <para>During reboot, the script <command>/etc/rc</command>
	    runs <command>ccdconfig -C</command> if <filename>/etc/ccd.conf</filename>
	    exists. This automatically configures the
	    &man.ccd.4; so it can be mounted.</para>

	  <note><para>If you are booting into single user mode, before you can
	    &man.mount.8; the &man.ccd.4;, you
	    need to issue the following command to configure the
	    array:</para>

	  <programlisting>ccdconfig -C</programlisting>
          </note>

	  <para>To automatically mount the &man.ccd.4;,
            place an entry for the &man.ccd.4; in
	    <filename>/etc/fstab</filename> so it will be mounted at
	    boot time:</para>

	  <programlisting>/dev/ccd0c              /media       ufs     rw      2       2</programlisting>
	</sect4>
      </sect3>

      <sect3 xml:id="vinum">
	<title>The Vinum Volume Manager</title>

<indexterm><primary>RAID</primary><secondary>software</secondary></indexterm>
<indexterm>
  <primary>RAID</primary>
  <secondary>Vinum</secondary>
</indexterm>

	<para>The Vinum Volume Manager is a block device driver which
	  implements virtual disk drives.  It isolates disk hardware
	  from the block device interface and maps data in ways which
	  result in an increase in flexibility, performance and
	  reliability compared to the traditional slice view of disk
	  storage.  &man.vinum.8; implements the RAID-0, RAID-1 and
	  RAID-5 models, both individually and in combination.</para>

	<para>See <xref linkend="vinum-vinum"/> for more
	  information about &man.vinum.8;.</para>
      </sect3>
    </sect2>

    <sect2 xml:id="raid-hard">
      <title>Hardware RAID</title>

      <indexterm>
	<primary>RAID</primary>
	<secondary>hardware</secondary>
      </indexterm>

      <para>FreeBSD also supports a variety of hardware <acronym>RAID</acronym>
        controllers.  These devices control a <acronym>RAID</acronym> subsystem
        without the need for FreeBSD specific software to manage the
        array.</para>

      <para>Using an on-card <acronym>BIOS</acronym>, the card controls most  of the disk operations
	itself.  The following is a brief setup description using a Promise <acronym>IDE</acronym> <acronym>RAID</acronym>
	controller.  When this card is installed and the system is started up, it
	displays a prompt requesting information.  Follow the instructions
	to enter the card's setup screen.  From here, you have the ability to
	combine all the attached drives.  After doing so, the disk(s) will look like
	a single drive to FreeBSD.  Other <acronym>RAID</acronym> levels can be set up
	accordingly.
      </para>
    </sect2>

    <sect2>
      <title>Rebuilding ATA RAID1 Arrays</title>

      <para>FreeBSD allows you to hot-replace a failed disk in an array. This requires
	that you catch it before you reboot.</para>

      <para>You will probably see something like the following in <filename>/var/log/messages</filename> or in the &man.dmesg.8;
	output:</para>

      <programlisting>ad6 on monster1 suffered a hard error.
ad6: READ command timeout tag=0 serv=0 - resetting
ad6: trying fallback to PIO mode
ata3: resetting devices .. done
ad6: hard error reading fsbn 1116119 of 0-7 (ad6 bn 1116119; cn 1107 tn 4 sn 11)\\
status=59 error=40
ar0: WARNING - mirror lost</programlisting>

      <para>Using &man.atacontrol.8;, check for further information:</para>

      <screen>&prompt.root; <userinput>atacontrol list</userinput>
ATA channel 0:
	Master:      no device present
	Slave:   acd0 &lt;HL-DT-ST CD-ROM GCR-8520B/1.00&gt; ATA/ATAPI rev 0

ATA channel 1:
	Master:      no device present
	Slave:       no device present

ATA channel 2:
	Master:  ad4 &lt;MAXTOR 6L080J4/A93.0500&gt; ATA/ATAPI rev 5
	Slave:       no device present

ATA channel 3:
	Master:  ad6 &lt;MAXTOR 6L080J4/A93.0500&gt; ATA/ATAPI rev 5
	Slave:       no device present

&prompt.root; <userinput>atacontrol status ar0</userinput>
ar0: ATA RAID1 subdisks: ad4 ad6 status: DEGRADED</screen>

      <procedure>
	<step>
	  <para>You will first need to detach the ata channel with the failed
	    disk so you can safely remove it:</para>

	  <screen>&prompt.root; <userinput>atacontrol detach ata3</userinput></screen>
	</step>

	<step>
	  <para>Replace the disk.</para>
	</step>

	<step>
	  <para>Reattach the ata channel:</para>

	  <screen>&prompt.root; <userinput>atacontrol attach ata3</userinput>
Master:  ad6 &lt;MAXTOR 6L080J4/A93.0500&gt; ATA/ATAPI rev 5
Slave:   no device present</screen>
	</step>

	<step>
	  <para>Add the new disk to the array as a spare:</para>

	  <screen>&prompt.root; <userinput>atacontrol addspare ar0 ad6</userinput></screen>
	</step>

	<step>
	  <para>Rebuild the array:</para>

	  <screen>&prompt.root; <userinput>atacontrol rebuild ar0</userinput></screen>
	</step>

	<step>
	  <para>It is possible to check on the progress by issuing the
	    following command:</para>

	  <screen>&prompt.root; <userinput>dmesg | tail -10</userinput>
[output removed]
ad6: removed from configuration
ad6: deleted from ar0 disk1
ad6: inserted into ar0 disk1 as spare

&prompt.root; <userinput>atacontrol status ar0</userinput>
ar0: ATA RAID1 subdisks: ad4 ad6 status: REBUILDING 0% completed</screen>
	</step>

	<step>
	  <para>Wait until this operation completes.</para>
	</step>
      </procedure>
    </sect2>
  </sect1>

  <sect1 xml:id="usb-disks">
    <info><title>USB Storage Devices</title>
      <authorgroup>
	<author><personname><firstname>Marc</firstname><surname>Fonvieille</surname></personname><contrib>Contributed by </contrib></author>
      </authorgroup>
      
    </info>

    
    <indexterm>
      <primary>USB</primary>
      <secondary>disks</secondary>
    </indexterm>

    <para>A lot of external storage solutions, nowadays, use the
      Universal Serial Bus (USB): hard drives, USB thumbdrives, CD-R
      burners, etc.  &os; provides support for these devices.</para>

    <sect2>
      <title>Configuration</title>

      <para>The USB mass storage devices driver, &man.umass.4;,
	provides the support for USB storage devices.  If you use the
	<filename>GENERIC</filename> kernel, you do not have to change
	anything in your configuration.  If you use a custom kernel,
	be sure that the following lines are present in your kernel
	configuration file:</para>

      <programlisting>device scbus
device da
device pass
device uhci
device ohci
device usb
device umass</programlisting>

      <para>The &man.umass.4; driver uses the SCSI subsystem to access
	to the USB storage devices, your USB device will be seen as a
	SCSI device by the system.  Depending on the USB chipset on
	your motherboard, you only need either <literal>device
	uhci</literal> or <literal>device ohci</literal>, however
	having both in the kernel configuration file is harmless.  Do
	not forget to compile and install the new kernel if you added
	any lines.</para>

      <note>
	<para>If your USB device is a CD-R or DVD burner, the SCSI CD-ROM
	  driver, &man.cd.4;, must be added to the kernel via the
	  line:</para>

	<programlisting>device cd</programlisting>

	<para>Since the burner is seen as a SCSI drive, the driver
	  &man.atapicam.4; should not be used in the kernel
	  configuration.</para>
      </note>

      <para>Support for USB 2.0 controllers is provided on
	&os;; however, you must add:</para>

      <programlisting>device ehci</programlisting>

      <para>to your configuration file for USB 2.0 support.  Note
	&man.uhci.4; and &man.ohci.4; drivers are still needed if you
	want USB 1.X support.</para>
    </sect2>

    <sect2>
      <title>Testing the Configuration</title>

      <para>The configuration is ready to be tested: plug in your USB
	device, and in the system message buffer (&man.dmesg.8;), the
	drive should appear as something like:</para>

      <screen>umass0: USB Solid state disk, rev 1.10/1.00, addr 2
GEOM: create disk da0 dp=0xc2d74850
da0 at umass-sim0 bus 0 target 0 lun 0
da0: &lt;Generic Traveling Disk 1.11&gt; Removable Direct Access SCSI-2 device
da0: 1.000MB/s transfers
da0: 126MB (258048 512 byte sectors: 64H 32S/T 126C)</screen>

      <para>Of course, the brand, the device node
	(<filename>da0</filename>) and other details can differ
	according to your configuration.</para>

      <para>Since the USB device is seen as a SCSI one, the
	<command>camcontrol</command> command can be used to list the
	USB storage devices attached to the system:</para>

      <screen>&prompt.root; <userinput>camcontrol devlist</userinput>
&lt;Generic Traveling Disk 1.11&gt;      at scbus0 target 0 lun 0 (da0,pass0)</screen>

      <para>If the drive comes with a file system, you should be able
	to mount it.  The <xref linkend="disks-adding"/> will help you
	to format and create partitions on the USB drive if
	needed.</para>

      <para>To make this device mountable as a normal user, certain
	steps have to be taken.  First, the devices that are created
	when a USB storage device is connected need to be accessible
	by the user.  A solution is to make all users of these devices
	a member of the <systemitem class="groupname">operator</systemitem> group.  This
	is done with &man.pw.8;.  Second, when the devices are
	created, the <systemitem class="groupname">operator</systemitem> group should be
	able to read and write them.  This is accomplished by adding
	these lines to
	<filename>/etc/devfs.rules</filename>:</para>

      <programlisting>[localrules=1]
add path 'da*' mode 0660 group operator</programlisting>

      <note>
	<para>If there already are SCSI disks in the system, it must
	  be done a bit different.  E.g., if the system already
	  contains disks <filename>da0</filename> through
	  <filename>da2</filename> attached to the system, change
	  the second line as follows:</para>

	<programlisting>add path 'da[3-9]*' mode 0660 group operator</programlisting>

	<para>This will exclude the already existing disks from
	  belonging to the <systemitem class="groupname">operator</systemitem>
	  group.</para>
      </note>

      <para>You also have to enable your &man.devfs.rules.5; ruleset
	in your <filename>/etc/rc.conf</filename> file:</para>

      <programlisting>devfs_system_ruleset="localrules"</programlisting>

      <para>Next, the kernel has to be configured to allow regular
	users to mount file systems.  The easiest way is to add the
	following line to
	<filename>/etc/sysctl.conf</filename>:</para>

      <programlisting>vfs.usermount=1</programlisting>

      <para>Note that this only takes effect after the next reboot.
	Alternatively, one can also use &man.sysctl.8; to set this
	variable.</para>

      <para>The final step is to create a directory where the file
	system is to be mounted.  This directory needs to be owned by
	the user that is to mount the file system.  One way to do that
	is for <systemitem class="username">root</systemitem> to create a subdirectory
	owned by that user as
	<filename>/mnt/$USER</filename>
	(replace <replaceable>$USER</replaceable> by the login name of
	the actual user):</para>

      <screen>&prompt.root; <userinput>mkdir /mnt/$USER</userinput>
&prompt.root; <userinput>chown $USER:$USER /mnt/$USER</userinput></screen>

      <para>Suppose a USB thumbdrive is plugged in, and a device
	<filename>/dev/da0s1</filename> appears.  Since these devices
	usually come preformatted with a FAT file system, one can
	mount them like this:</para>

      <screen>&prompt.user; <userinput>mount_msdosfs -m 644 -M 755 /dev/da0s1 /mnt/$USER</userinput></screen>

      <para>If you unplug the device (the disk must be unmounted
	before), you should see, in the system message buffer,
	something like the following:</para>

      <screen>umass0: at uhub0 port 1 (addr 2) disconnected
(da0:umass-sim0:0:0:0): lost device
(da0:umass-sim0:0:0:0): removing device entry
GEOM: destroy disk da0 dp=0xc2d74850
umass0: detached</screen>
    </sect2>

    <sect2>
      <title>Further Reading</title>

      <para>Beside the <link linkend="disks-adding">Adding
	Disks</link> and <link linkend="mount-unmount">Mounting and
	Unmounting File Systems</link> sections, reading various
	manual pages may be also useful: &man.umass.4;,
	&man.camcontrol.8;, and &man.usbdevs.8;.</para>
    </sect2>
  </sect1>

  <sect1 xml:id="creating-cds">
    <info><title>Creating and Using Optical Media (CDs)</title>
      <authorgroup>
	<author><personname><firstname>Mike</firstname><surname>Meyer</surname></personname><contrib>Contributed by </contrib></author>
      </authorgroup>
      
    </info>

    
    <indexterm>
      <primary>CDROMs</primary>
      <secondary>creating</secondary>
    </indexterm>

    <sect2>
      <title>Introduction</title>

      <para>CDs have a number of features that differentiate them from
	conventional disks. Initially, they were not writable by the
	user. They are designed so that they can be read continuously without
	delays to move the head between tracks. They are also much easier
	to transport between systems than similarly sized media were at the
	time.</para>

      <para>CDs do have tracks, but this refers to a section of data to
	be read continuously and not a physical property of the disk. To
	produce a CD on FreeBSD, you prepare the data files that are going
	to make up the tracks on the CD, then write the tracks to the
	CD.</para>

      <indexterm><primary>ISO 9660</primary></indexterm>
      <indexterm>
        <primary>file systems</primary>
        <secondary>ISO 9660</secondary>
      </indexterm>
      <para>The ISO 9660 file system was designed to deal with these
	differences. It unfortunately codifies file system limits that were
	common then. Fortunately, it provides an extension mechanism that
	allows properly written CDs to exceed those limits while still
	working with systems that do not support those extensions.</para>

      <indexterm>
        <primary><package>sysutils/cdrtools</package></primary>
      </indexterm>
      <para>The <package>sysutils/cdrtools</package>
	port includes &man.mkisofs.8;, a program that you can use to
	produce a data file containing an ISO 9660 file
	system. It has options that support various extensions, and is
	described below.</para>

      <indexterm>
        <primary>CD burner</primary>
        <secondary>ATAPI</secondary>
      </indexterm>
      <para>Which tool to use to burn the CD depends on whether your CD burner
	is ATAPI or something else. ATAPI CD burners use the <command>burncd</command> program that is part of
	the base system. SCSI and USB CD burners should use
	<command>cdrecord</command> from
	the <package>sysutils/cdrtools</package> port.
	It is also possible to use <command>cdrecord</command> and other tools
	for SCSI drives on ATAPI hardware with the <link linkend="atapicam">ATAPI/CAM module</link>.</para>

      <para>If you want CD burning software with a graphical user
	interface, you may wish to take a look at either
	<application>X-CD-Roast</application> or
	<application>K3b</application>.  These tools are available as
	packages or from the <package>sysutils/xcdroast</package> and <package>sysutils/k3b</package> ports.
	<application>X-CD-Roast</application> and
	<application>K3b</application> require the <link linkend="atapicam">ATAPI/CAM module</link> with ATAPI
	hardware.</para>
    </sect2>

    <sect2 xml:id="mkisofs">
      <title>mkisofs</title>

      <para>The &man.mkisofs.8; program, which is part of the
	<package>sysutils/cdrtools</package> port,
        produces an ISO 9660 file system
	that is an image of a directory tree in the &unix; file system name
	space. The simplest usage is:</para>

      <screen>&prompt.root; <userinput>mkisofs -o imagefile.iso /path/to/tree</userinput></screen>

      <indexterm>
        <primary>file systems</primary>
        <secondary>ISO 9660</secondary>
      </indexterm>
      <para>This command will create an <replaceable>imagefile.iso</replaceable>
	containing an ISO 9660 file system that is a copy of the tree at
	<replaceable>/path/to/tree</replaceable>. In the process, it will
	map the file names to names that fit the limitations of the
	standard ISO 9660 file system, and will exclude files that have
	names uncharacteristic of ISO file systems.</para>

      <indexterm>
        <primary>file systems</primary>
        <secondary>HFS</secondary>
      </indexterm>
      <indexterm>
        <primary>file systems</primary>
        <secondary>Joliet</secondary>
      </indexterm>
      <para>A number of options are available to overcome those
	restrictions. In particular, <option>-R</option> enables the
	Rock Ridge extensions common to &unix; systems, <option>-J</option>
	enables Joliet extensions used by Microsoft systems, and
	<option>-hfs</option> can be used to create HFS file systems used
	by &macos;.</para>

      <para>For CDs that are going to be used only on FreeBSD systems,
	<option>-U</option> can be used to disable all filename
	restrictions. When used with <option>-R</option>, it produces a
	file system image that is identical to the FreeBSD tree you started
	from, though it may violate the ISO 9660 standard in a number of
	ways.</para>

      <indexterm>
        <primary>CDROMs</primary>
        <secondary>creating bootable</secondary>
      </indexterm>
      <para>The last option of general use is <option>-b</option>. This is
	used to specify the location of the boot image for use in producing an
	<quote>El Torito</quote> bootable CD. This option takes an
	argument which is the path to a boot image from the top of the
	tree being written to the CD. By default, &man.mkisofs.8; creates an
	ISO image in the so-called <quote>floppy disk emulation</quote> mode,
	and thus expects the boot image to be exactly 1200, 1440 or
	2880&nbsp;KB in size. Some boot loaders, like the one used by the
	FreeBSD distribution disks, do not use emulation mode; in this case,
	the <option>-no-emul-boot</option> option should be used. So, if
	<filename>/tmp/myboot</filename> holds a bootable FreeBSD system
	with the boot image in
	<filename>/tmp/myboot/boot/cdboot</filename>, you could produce the
	image of an ISO 9660 file system in
	<filename>/tmp/bootable.iso</filename> like so:</para>

      <screen>&prompt.root; <userinput>mkisofs -R -no-emul-boot -b boot/cdboot -o /tmp/bootable.iso /tmp/myboot</userinput></screen>

      <para>Having done that, if you have <filename>md</filename>
	configured in your kernel, you can mount the file system with:</para>

      <screen>&prompt.root; <userinput>mdconfig -a -t vnode -f /tmp/bootable.iso -u 0</userinput>
&prompt.root; <userinput>mount -t cd9660 /dev/md0 /mnt</userinput></screen>

      <para>At which point you can verify that <filename>/mnt</filename>
	and <filename>/tmp/myboot</filename> are identical.</para>

      <para>There are many other options you can use with
	&man.mkisofs.8; to fine-tune its behavior.  In particular:
	modifications to an ISO 9660 layout and the creation of Joliet
	and HFS discs.  See the	&man.mkisofs.8; manual page for details.</para>
    </sect2>

    <sect2 xml:id="burncd">
      <title>burncd</title>
      <indexterm>
        <primary>CDROMs</primary>
        <secondary>burning</secondary>
      </indexterm>
      <para>If you have an ATAPI CD burner, you can use the
	<command>burncd</command> command to burn an ISO image onto a
	CD. <command>burncd</command> is part of the base system, installed
	as <filename>/usr/sbin/burncd</filename>.  Usage is very simple, as
	it has few options:</para>

      <screen>&prompt.root; <userinput>burncd -f cddevice data imagefile.iso fixate</userinput></screen>

      <para>Will burn a copy of <replaceable>imagefile.iso</replaceable> on
	<replaceable>cddevice</replaceable>. The default device is
	<filename>/dev/acd0</filename>.  See &man.burncd.8; for options to
	set the write speed, eject the CD after burning, and write audio
	data.</para>
    </sect2>

    <sect2 xml:id="cdrecord">
      <title>cdrecord</title>

      <para>If you do not have an ATAPI CD burner, you will have to use
	<command>cdrecord</command> to burn your
	CDs. <command>cdrecord</command> is not part of the base system;
	you must install it from either the port at <package>sysutils/cdrtools</package>
	or the appropriate
	package. Changes to the base system can cause binary versions of
	this program to fail, possibly resulting in a
	<quote>coaster</quote>. You should therefore either upgrade the
	port when you upgrade your system, or if you are <link linkend="stable">tracking -STABLE</link>, upgrade the port when a
	new version becomes available.</para>

      <para>While <command>cdrecord</command> has many options, basic usage
	is even simpler than <command>burncd</command>. Burning an ISO 9660
	image is done with:</para>

      <screen>&prompt.root; <userinput>cdrecord dev=device imagefile.iso</userinput></screen>

      <para>The tricky part of using <command>cdrecord</command> is finding
	the <option>dev</option> to use. To find the proper setting, use
	the <option>-scanbus</option> flag of <command>cdrecord</command>,
	which might produce results like this:</para>
      <indexterm>
        <primary>CDROMs</primary>
        <secondary>burning</secondary>
      </indexterm>
      <screen>&prompt.root; <userinput>cdrecord -scanbus</userinput>
Cdrecord-Clone 2.01 (i386-unknown-freebsd7.0) Copyright (C) 1995-2004 J&ouml;rg Schilling
Using libscg version 'schily-0.1'
scsibus0:
        0,0,0     0) 'SEAGATE ' 'ST39236LW       ' '0004' Disk
        0,1,0     1) 'SEAGATE ' 'ST39173W        ' '5958' Disk
        0,2,0     2) *
        0,3,0     3) 'iomega  ' 'jaz 1GB         ' 'J.86' Removable Disk
        0,4,0     4) 'NEC     ' 'CD-ROM DRIVE:466' '1.26' Removable CD-ROM
        0,5,0     5) *
        0,6,0     6) *
        0,7,0     7) *
scsibus1:
        1,0,0   100) *
        1,1,0   101) *
        1,2,0   102) *
        1,3,0   103) *
        1,4,0   104) *
        1,5,0   105) 'YAMAHA  ' 'CRW4260         ' '1.0q' Removable CD-ROM
        1,6,0   106) 'ARTEC   ' 'AM12S           ' '1.06' Scanner
        1,7,0   107) *</screen>

      <para>This lists the appropriate <option>dev</option> value for the
	devices on the list. Locate your CD burner, and use the three
	numbers separated by commas as the value for
	<option>dev</option>. In this case, the CRW device is 1,5,0, so the
	appropriate input would be
	<option>dev=1,5,0</option>. There are easier
	ways to specify this value; see &man.cdrecord.1; for
	details. That is also the place to look for information on writing
	audio tracks, controlling the speed, and other things.</para>
    </sect2>

    <sect2 xml:id="duplicating-audiocds">
      <title>Duplicating Audio CDs</title>

      <para>You can duplicate an audio CD by extracting the audio data from
	the CD to a series of files, and then writing these files to a blank
	CD.  The process is slightly different for ATAPI and SCSI
	drives.</para>

      <procedure>
	<title>SCSI Drives</title>

	<step>
	  <para>Use <command>cdda2wav</command> to extract the audio.</para>

	  <screen>&prompt.user; <userinput>cdda2wav -v255 -D2,0 -B -Owav</userinput></screen>
	</step>

	<step>
	  <para>Use <command>cdrecord</command> to write the
	    <filename>.wav</filename> files.</para>

	  <screen>&prompt.user; <userinput>cdrecord -v dev=2,0 -dao -useinfo  *.wav</userinput></screen>

	  <para>Make sure that <replaceable>2,0</replaceable> is set
	    appropriately, as described in <xref linkend="cdrecord"/>.</para>
	</step>
      </procedure>

      <procedure>
	<title>ATAPI Drives</title>

	<step>
	  <para>The ATAPI CD driver makes each track available as
	    <filename>/dev/acddtnn</filename>,
	    where <replaceable>d</replaceable> is the drive number, and
	    <replaceable>nn</replaceable> is the track number written with two
	    decimal digits, prefixed with zero as needed.
	    So the first track on the first disk is
	    <filename>/dev/acd0t01</filename>, the second is
	    <filename>/dev/acd0t02</filename>, the third is
	    <filename>/dev/acd0t03</filename>, and so on.</para>

	  <para>Make sure the appropriate files exist in
	    <filename>/dev</filename>.  If the entries are missing,
	    force the system to retaste the media:</para>

	  <screen>&prompt.root; <userinput>dd if=/dev/acd0 of=/dev/null count=1</userinput></screen>
	</step>

	<step>
	  <para>Extract each track using &man.dd.1;.  You must also use a
	    specific block size when extracting the files.</para>

	  <screen>&prompt.root; <userinput>dd if=/dev/acd0t01 of=track1.cdr bs=2352</userinput>
&prompt.root; <userinput>dd if=/dev/acd0t02 of=track2.cdr bs=2352</userinput>
...
</screen>
	</step>

	<step>
	  <para>Burn the extracted files to disk using
	    <command>burncd</command>.  You must specify that these are audio
	    files, and that <command>burncd</command> should fixate the disk
	    when finished.</para>

	  <screen>&prompt.root; <userinput>burncd -f /dev/acd0 audio track1.cdr track2.cdr ... fixate</userinput></screen>
	</step>
      </procedure>
    </sect2>

    <sect2 xml:id="imaging-cd">
      <title>Duplicating Data CDs</title>

      <para>You can copy a data CD to a image file that is
	functionally equivalent to the image file created with
        &man.mkisofs.8;, and you can use it to duplicate
	any data CD.  The example given here assumes that your CDROM
	device is <filename>acd0</filename>.  Substitute your
	correct CDROM device.</para>

      <screen>&prompt.root; <userinput>dd if=/dev/acd0 of=file.iso bs=2048</userinput></screen>

      <para>Now that you have an image, you can burn it to CD as
	described above.</para>
    </sect2>

    <sect2 xml:id="mounting-cd">
      <title>Using Data CDs</title>

      <para>Now that you have created a standard data CDROM, you
	probably want to mount it and read the data on it.  By
	default, &man.mount.8; assumes that a file system is of type
	<literal>ufs</literal>.  If you try something like:</para>

      <screen>&prompt.root; <userinput>mount /dev/cd0 /mnt</userinput></screen>

      <para>you will get a complaint about <errorname>Incorrect super
	  block</errorname>, and no mount. The CDROM is not a
	  <literal>UFS</literal> file system, so attempts to mount it
	  as such will fail.  You just need to tell &man.mount.8; that
	  the file system is of type <literal>ISO9660</literal>, and
	  everything will work.  You do this by specifying the
	  <option>-t cd9660</option> option &man.mount.8;. For
	  example, if you want to mount the CDROM device,
	  <filename>/dev/cd0</filename>, under
	  <filename>/mnt</filename>, you would execute:</para>

          <screen>&prompt.root; <userinput>mount -t cd9660 /dev/cd0 /mnt</userinput></screen>

      <para>Note that your device name
	(<filename>/dev/cd0</filename> in this example) could be
	different, depending on the interface your CDROM uses. Also,
	the <option>-t cd9660</option> option just executes
	&man.mount.cd9660.8;. The above example could be shortened
	to:</para>

<screen>&prompt.root; <userinput>mount_cd9660 /dev/cd0 /mnt</userinput></screen>

      <para>You can generally use data CDROMs from any vendor in this
	way.  Disks with certain ISO 9660 extensions might behave
	oddly, however.  For example, Joliet disks store all filenames
	in two-byte Unicode characters.  The FreeBSD kernel does not
	speak Unicode, but the &os; CD9660 driver is able to convert
	Unicode characters on the fly.  If some non-English characters
	show up as question marks you will need to specify the local
	charset you use with the <option>-C</option> option.  For more
	information, consult the &man.mount.cd9660.8; manual
	page.</para>

      <note>
	<para>To be able to do this character conversion with the help
	  of the <option>-C</option> option, the kernel will require
	  the <filename>cd9660_iconv.ko</filename> module to be
	  loaded.  This can be done either by adding this line to
	  <filename>loader.conf</filename>:</para>

	<programlisting>cd9660_iconv_load="YES"</programlisting>

	<para>and then rebooting the machine, or by directly loading the
	  module with &man.kldload.8;.</para>
      </note>

      <para>Occasionally, you might get <errorname>Device not
	configured</errorname> when trying to mount a CDROM.  This
	usually means that the CDROM drive thinks that there is no
	disk in the tray, or that the drive is not visible on the bus.
	It can take a couple of seconds for a CDROM drive to realize
	that it has been fed, so be patient.</para>

      <para>Sometimes, a SCSI CDROM may be missed because it did not
	have enough time to answer the bus reset.  If you have a SCSI
	CDROM please add the following option to your kernel
	configuration and <link linkend="kernelconfig-building">rebuild your kernel</link>.</para>

      <programlisting>options SCSI_DELAY=15000</programlisting>

      <para>This tells your SCSI bus to pause 15 seconds during boot,
	to give your CDROM drive every possible chance to answer the
	bus reset.</para>
    </sect2>

    <sect2 xml:id="rawdata-cd">
      <title>Burning Raw Data CDs</title>

      <para>You can choose to burn a file directly to CD, without
	creating an ISO 9660 file system.  Some people do this for
	backup purposes.  This runs more quickly than burning a
	standard CD:</para>

      <screen>&prompt.root; <userinput>burncd -f /dev/acd1 -s 12 data archive.tar.gz fixate</userinput></screen>

      <para>In order to retrieve the data burned to such a CD, you
	  must read data from the raw device node:</para>

      <screen>&prompt.root; <userinput>tar xzvf /dev/acd1</userinput></screen>

      <para>You cannot mount this disk as you would a normal CDROM.
	  Such a CDROM cannot be read under any operating system
	  except FreeBSD.  If you want to be able to mount the CD, or
	  share data with another operating system, you must use
	  &man.mkisofs.8; as described above.</para>
    </sect2>

    <sect2 xml:id="atapicam">
      <info><title>Using the ATAPI/CAM Driver</title>
	<authorgroup>
	  <author><personname><firstname>Marc</firstname><surname>Fonvieille</surname></personname><contrib>Contributed by </contrib></author>
	</authorgroup>
      </info>

      

      <indexterm>
	<primary>CD burner</primary>
	<secondary>ATAPI/CAM driver</secondary>
      </indexterm>

      <para>This driver allows ATAPI devices (CD-ROM, CD-RW, DVD
	drives etc...) to be accessed through the SCSI subsystem, and
	so allows the use of applications like <package>sysutils/cdrdao</package> or
	&man.cdrecord.1;.</para>

      <para>To use this driver, you will need to add the following
	line to the <filename>/boot/loader.conf</filename>
	file:</para>

      <programlisting>atapicam_load="YES"</programlisting>

      <para>then, reboot your machine.</para>

      <note>
	<para>If you prefer to statically compile the &man.atapicam.4;
	  support in your kernel, you will have to add this line to
	  your kernel configuration file:</para>

      <programlisting>device atapicam</programlisting>

      <para>You also need the following lines in your kernel
	configuration file:</para>

      <programlisting>device ata
device scbus
device cd
device pass</programlisting>

	<para>which should already be present.  Then rebuild, install
	  your new kernel, and reboot your machine.</para>
      </note>

      <para>During the boot process, your burner should show up,
	like so:</para>

      <screen>acd0: CD-RW &lt;MATSHITA CD-RW/DVD-ROM UJDA740&gt; at ata1-master PIO4
cd0 at ata1 bus 0 target 0 lun 0
cd0: &lt;MATSHITA CDRW/DVD UJDA740 1.00&gt; Removable CD-ROM SCSI-0 device
cd0: 16.000MB/s transfers
cd0: Attempt to query device size failed: NOT READY, Medium not present - tray closed</screen>

      <para>The drive could now be accessed via the
	<filename>/dev/cd0</filename> device name, for example to
	mount a CD-ROM on <filename>/mnt</filename>, just type the
	following:</para>

      <screen>&prompt.root; <userinput>mount -t cd9660 /dev/cd0 /mnt</userinput></screen>

      <para>As <systemitem class="username">root</systemitem>, you can run the following
	command to get the SCSI address of the burner:</para>

      <screen>&prompt.root; <userinput>camcontrol devlist</userinput>
&lt;MATSHITA CDRW/DVD UJDA740 1.00&gt;   at scbus1 target 0 lun 0 (pass0,cd0)</screen>

      <para>So <literal>1,0,0</literal> will be the SCSI address to
	use with &man.cdrecord.1; and other SCSI application.</para>

      <para>For more information about ATAPI/CAM and SCSI system,
	refer to the &man.atapicam.4; and &man.cam.4; manual
	pages.</para>
    </sect2>
  </sect1>

  <sect1 xml:id="creating-dvds">
    <info><title>Creating and Using Optical Media (DVDs)</title>
      <authorgroup>
	<author><personname><firstname>Marc</firstname><surname>Fonvieille</surname></personname><contrib>Contributed by </contrib></author>
      </authorgroup>
      <authorgroup>
	<author><personname><firstname>Andy</firstname><surname>Polyakov</surname></personname><contrib>With inputs from </contrib></author>
      </authorgroup>
      
    </info>

    
    <indexterm>
      <primary>DVD</primary>
      <secondary>burning</secondary>
    </indexterm>

    <sect2>
      <title>Introduction</title>

      <para>Compared to the CD, the DVD is the next generation of
	optical media storage technology.  The DVD can hold more data
	than any CD and is nowadays the standard for video
	publishing.</para>

      <para>Five physical recordable formats can be defined for what
	we will call a recordable DVD:</para>

      <itemizedlist>
	<listitem>
	  <para>DVD-R: This was the first DVD recordable format
	    available.  The DVD-R standard is defined by the <link xlink:href="http://www.dvdforum.com/forum.shtml">DVD Forum</link>.
	    This format is write once.</para>
	</listitem>

	<listitem>
	  <para>DVD-RW: This is the rewritable version of
	    the DVD-R standard.  A DVD-RW can be rewritten about 1000
	    times.</para>
	</listitem>

	<listitem>
	  <para>DVD-RAM: This is also a rewritable format
	    supported by the DVD Forum.  A DVD-RAM can be seen as a
	    removable hard drive.  However, this media is not
	    compatible with most DVD-ROM drives and DVD-Video players;
	    only a few DVD writers support the DVD-RAM format.  Read
	    the <xref linkend="creating-dvd-ram"/> for more information
	    on DVD-RAM use.</para>
	</listitem>

	<listitem>
	  <para>DVD+RW: This is a rewritable format defined by
	    the <link xlink:href="http://www.dvdrw.com/">DVD+RW
	    Alliance</link>.  A DVD+RW can be rewritten about 1000
	    times.</para>
	</listitem>

	<listitem>
	  <para>DVD+R: This format is the write once variation
	    of the DVD+RW format.</para>
	</listitem>
      </itemizedlist>

      <para>A single layer recordable DVD can hold up to
	4,700,000,000&nbsp;bytes which is actually 4.38&nbsp;GB or
	4485&nbsp;MB (1 kilobyte is 1024 bytes).</para>

      <note>
	<para>A distinction must be made between the physical media and
	  the application.   For example, a DVD-Video is a specific
	  file layout that can be written on any recordable DVD
	  physical media: DVD-R, DVD+R, DVD-RW etc.  Before choosing
	  the type of media, you must be sure that both the burner and the
	  DVD-Video player (a standalone player or a DVD-ROM drive on
	  a computer) are compatible with the media under consideration.</para></note>
    </sect2>

    <sect2>
      <title>Configuration</title>

      <para>The program &man.growisofs.1; will be used to perform DVD
	recording.  This command is part of the
	<application>dvd+rw-tools</application> utilities (<package>sysutils/dvd+rw-tools</package>).  The
	<application>dvd+rw-tools</application> support all DVD media
	types.</para>

      <para>These tools use the SCSI subsystem to access to the
	devices, therefore the <link linkend="atapicam">ATAPI/CAM
	support</link> must be added to your kernel.  If your burner
	uses the USB interface this addition is useless, and you should
	read the <xref linkend="usb-disks"/> for more details on USB
	devices configuration.</para>

      <para>You also have to enable DMA access for ATAPI devices, this
	can be done in adding the following line to the
	<filename>/boot/loader.conf</filename> file:</para>

      <programlisting>hw.ata.atapi_dma="1"</programlisting>

      <para>Before attempting to use the
	<application>dvd+rw-tools</application> you should consult the
	<link xlink:href="http://fy.chalmers.se/~appro/linux/DVD+RW/hcn.html">dvd+rw-tools'
	hardware compatibility notes</link> for any information
	related to your DVD burner.</para>

      <note>
	<para>If you want a graphical user interface, you should have
	  a look to <application>K3b</application> (<package>sysutils/k3b</package>) which provides a
	  user friendly interface to &man.growisofs.1; and many other
	  burning tools.</para>
      </note>
    </sect2>

    <sect2>
      <title>Burning Data DVDs</title>

      <para>The &man.growisofs.1; command is a frontend to <link linkend="mkisofs">mkisofs</link>, it will invoke
	&man.mkisofs.8; to create the file system layout and will
	perform the write on the DVD.  This means you do not need to
	create an image of the data before the burning process.</para>

      <para>To burn onto a DVD+R or a DVD-R the data from the <filename>/path/to/data</filename> directory, use the
	following command:</para>

      <screen>&prompt.root; <userinput>growisofs -dvd-compat -Z /dev/cd0 -J -R /path/to/data</userinput></screen>

      <para>The options <option>-J -R</option> are passed to
	&man.mkisofs.8; for the file system creation (in this case: an
	ISO 9660 file system with Joliet and Rock Ridge extensions),
	consult the &man.mkisofs.8; manual page for more
	details.</para>

      <para>The option <option>-Z</option> is used for the initial
	session recording in any case: multiple sessions or not.  The
	DVD device, <replaceable>/dev/cd0</replaceable>, must be
	changed according to your configuration.  The
	<option>-dvd-compat</option> parameter will close the disk,
	the recording will be unappendable.  In return this should provide better
	media compatibility with DVD-ROM drives.</para>

      <para>It is also possible to burn a pre-mastered image, for
	example to burn the image
	<replaceable>imagefile.iso</replaceable>, we will run:</para>

      <screen>&prompt.root; <userinput>growisofs -dvd-compat -Z /dev/cd0=imagefile.iso</userinput></screen>

      <para>The write speed should be detected and automatically set
	according to the media and the drive being used.  If you want
	to force the write speed, use the <option>-speed=</option>
	parameter.  For more information, read the &man.growisofs.1;
	manual page.</para>
    </sect2>

    <sect2>
      <title>Burning a DVD-Video</title>

      <indexterm>
	<primary>DVD</primary>
	<secondary>DVD-Video</secondary>
      </indexterm>

      <para>A DVD-Video is a specific file layout based on ISO 9660
	and the micro-UDF (M-UDF) specifications.  The DVD-Video also
	presents a specific data structure hierarchy, it is the reason
	why you need a particular program such as <package>multimedia/dvdauthor</package> to author the
	DVD.</para>

      <para>If you already have an image of the DVD-Video file system,
	just burn it in the same way as for any image, see the
	previous section for an example.  If you have made the DVD
	authoring and the result is in, for example, the directory
	<filename>/path/to/video</filename>, the
	following command should be used to burn the DVD-Video:</para>

      <screen>&prompt.root; <userinput>growisofs -Z /dev/cd0 -dvd-video /path/to/video</userinput></screen>

      <para>The <option>-dvd-video</option> option will be passed down to
	&man.mkisofs.8; and will instruct it to create a DVD-Video file system
	layout.  Beside this, the <option>-dvd-video</option> option
	implies <option>-dvd-compat</option> &man.growisofs.1;
	option.</para>
    </sect2>

    <sect2>
      <title>Using a DVD+RW</title>

      <indexterm>
	<primary>DVD</primary>
	<secondary>DVD+RW</secondary>
      </indexterm>

      <para>Unlike CD-RW, a virgin DVD+RW needs to be formatted before
	first use.  The &man.growisofs.1; program will take care of it
	automatically whenever appropriate, which is the
	<emphasis>recommended</emphasis> way.  However you can use the
	<command>dvd+rw-format</command> command to format the
	DVD+RW:</para>

      <screen>&prompt.root; <userinput>dvd+rw-format /dev/cd0</userinput></screen>

      <para>You need to perform this operation just once, keep in mind
	that only virgin DVD+RW medias need to be formatted.  Then you
	can burn the DVD+RW in the way seen in previous
	sections.</para>

      <para>If you want to burn new data (burn a totally new file
	system not append some data) onto a DVD+RW, you do not need to
	blank it, you just have to write over the previous recording
	(in performing a new initial session), like this:</para>

      <screen>&prompt.root; <userinput>growisofs -Z /dev/cd0 -J -R /path/to/newdata</userinput></screen>

      <para>DVD+RW format offers the possibility to easily append data
	to a previous recording.  The operation consists in merging a
	new session to the existing one, it is not multisession
	writing, &man.growisofs.1; will <emphasis>grow</emphasis> the
	ISO 9660 file system present on the media.</para>

      <para>For example, if we want to append data to our previous
	DVD+RW, we have to use the following:</para>

      <screen>&prompt.root; <userinput>growisofs -M /dev/cd0 -J -R /path/to/nextdata</userinput></screen>

      <para>The same &man.mkisofs.8; options we used to burn the
	initial session should be used during next writes.</para>

      <note>
	<para>You may want to use the <option>-dvd-compat</option>
	  option if you want better media compatibility with DVD-ROM
	  drives.  In the DVD+RW case, this will not prevent you from
	  adding data.</para>
      </note>

      <para>If for any reason you really want to blank the media, do
	the following:</para>

      <screen>&prompt.root; <userinput>growisofs -Z /dev/cd0=/dev/zero</userinput></screen>
    </sect2>

    <sect2>
      <title>Using a DVD-RW</title>

      <indexterm>
	<primary>DVD</primary>
	<secondary>DVD-RW</secondary>
      </indexterm>

      <para>A DVD-RW accepts two disc formats: the incremental
	sequential one and the restricted overwrite.  By default
	DVD-RW discs are in sequential format.</para>

      <para>A virgin DVD-RW can be directly written without the need
	of a formatting operation, however a non-virgin DVD-RW in
	sequential format needs to be blanked before to be able to
	write a new initial session.</para>

      <para>To blank a DVD-RW in sequential mode, run:</para>

      <screen>&prompt.root; <userinput>dvd+rw-format -blank=full /dev/cd0</userinput></screen>

      <note>
	<para>A full blanking (<option>-blank=full</option>) will take
	  about one hour on a 1x media.  A fast blanking can be
	  performed using the <option>-blank</option> option if the
	  DVD-RW will be recorded in Disk-At-Once (DAO) mode.  To burn
	  the DVD-RW in DAO mode, use the command:</para>

	<screen>&prompt.root; <userinput>growisofs -use-the-force-luke=dao -Z /dev/cd0=imagefile.iso</userinput></screen>

	<para>The <option>-use-the-force-luke=dao</option> option
	  should not be required since &man.growisofs.1; attempts to
	  detect minimally (fast blanked) media and engage DAO
	  write.</para>

	<para>In fact one should use restricted overwrite mode with
	  any DVD-RW, this format is more flexible than the default
	  incremental sequential one.</para>
      </note>

      <para>To write data on a sequential DVD-RW, use the same
	instructions as for the other DVD formats:</para>

      <screen>&prompt.root; <userinput>growisofs -Z /dev/cd0 -J -R /path/to/data</userinput></screen>

      <para>If you want to append some data to your previous
	recording, you will have to use the &man.growisofs.1;
	<option>-M</option> option.  However, if you perform data
	addition on a DVD-RW in incremental sequential mode, a new
	session will be created on the disc and the result will be a
	multi-session disc.</para>

      <para>A DVD-RW in restricted overwrite format does not need to
	be blanked before a new initial session, you just have to
	overwrite the disc with the <option>-Z</option> option, this
	is similar to the DVD+RW case.  It is also possible to grow an
	existing ISO 9660 file system written on the disc in a same
	way as for a DVD+RW with the <option>-M</option> option.  The
	result will be a one-session DVD.</para>

      <para>To put a DVD-RW in the restricted overwrite format, the
	following command must be used:</para>

      <screen>&prompt.root; <userinput>dvd+rw-format /dev/cd0</userinput></screen>

      <para>To change back to the sequential format use:</para>

      <screen>&prompt.root; <userinput>dvd+rw-format -blank=full /dev/cd0</userinput></screen>
    </sect2>

    <sect2>
      <title>Multisession</title>

      <para>Very few DVD-ROM drives support
	multisession DVDs, they will most of time, hopefully, only read
	the first session.  DVD+R, DVD-R and DVD-RW in sequential
	format can accept multiple sessions, the notion of multiple
	sessions does not exist for the DVD+RW and the DVD-RW
	restricted overwrite formats.</para>

      <para>Using the following command after an initial (non-closed)
	session on a DVD+R, DVD-R, or DVD-RW in sequential format,
	will add a new session to the disc:</para>

      <screen>&prompt.root; <userinput>growisofs -M /dev/cd0 -J -R /path/to/nextdata</userinput></screen>

      <para>Using this command line with a DVD+RW or a DVD-RW in restricted
	overwrite mode, will append data in merging the new session to
	the existing one.  The result will be a single-session disc.
	This is the way used to add data after an initial write on these
	medias.</para>

      <note>
	<para>Some space on the media is used between each session for
	  end and start of sessions.  Therefore, one should add
	  sessions with large amount of data to optimize media space.
	  The number of sessions is limited to 154 for a DVD+R,
	  about 2000 for a DVD-R, and 127 for a DVD+R Double
	  Layer.</para>
      </note>
    </sect2>

    <sect2>
      <title>For More Information</title>

      <para>To obtain more information about a DVD, the
	<command>dvd+rw-mediainfo
	/dev/cd0</command> command can be
	ran with the disc in the drive.</para>

      <para>More information about the
	<application>dvd+rw-tools</application> can be found in
	the &man.growisofs.1; manual page, on the <link xlink:href="http://fy.chalmers.se/~appro/linux/DVD+RW/">dvd+rw-tools
	web site</link> and in the <link xlink:href="http://lists.debian.org/cdwrite/">cdwrite mailing
	list</link> archives.</para>

      <note>
	<para>The <command>dvd+rw-mediainfo</command> output of the
	  resulting recording or the media with issues is mandatory
	  for any problem report.  Without this output, it will be
	  quite impossible to help you.</para>
      </note>
    </sect2>

    <sect2 xml:id="creating-dvd-ram">
      <title>Using a DVD-RAM</title>
      <indexterm>
	<primary>DVD</primary>
	<secondary>DVD-RAM</secondary>
      </indexterm>

      <sect3>
	<title>Configuration</title>

	<para>DVD-RAM writers come with either SCSI or ATAPI
	  interface.  DMA access for ATAPI devices has to be enabled,
	  this can be done by adding the following line to the
	  <filename>/boot/loader.conf</filename> file:</para>

	<programlisting>hw.ata.atapi_dma="1"</programlisting>
      </sect3>

      <sect3>
	<title>Preparing the Medium</title>

	<para>As previously mentioned in the chapter introduction, a
	  DVD-RAM can be seen as a removable hard drive.  As any other
	  hard drive the DVD-RAM must be <quote>prepared</quote>
	  before the first use.  In the example, the whole
	  disk space will be used with a standard UFS2 file system:</para>

	<screen>&prompt.root; <userinput>dd if=/dev/zero of=/dev/acd0 count=2</userinput>
&prompt.root; <userinput>bsdlabel -Bw acd0</userinput>
&prompt.root; <userinput>newfs /dev/acd0</userinput></screen>

	<para>The DVD device, <filename>acd0</filename>, must be
	  changed according to the configuration.</para>
      </sect3>

      <sect3>
	<title>Using the Medium</title>

	<para>Once the previous operations have been performed on the
	  DVD-RAM, it can be mounted as a normal hard drive:</para>

	<screen>&prompt.root; <userinput>mount /dev/acd0 /mnt</userinput></screen>

	<para>After this the DVD-RAM will be both readable and writeable.</para>
      </sect3>
    </sect2>
  </sect1>

  <sect1 xml:id="floppies">
    <info><title>Creating and Using Floppy Disks</title>
      <authorgroup>
	<author><personname><firstname>Julio</firstname><surname>Merino</surname></personname><contrib>Original work by </contrib></author>
      </authorgroup>
      
      <authorgroup>
	<author><personname><firstname>Martin</firstname><surname>Karlsson</surname></personname><contrib>Rewritten by </contrib></author>
      </authorgroup>
      
    </info>

    

    <para>Storing data on floppy disks is sometimes useful, for
      example when one does not have any other removable storage media
      or when one needs to transfer small amounts of data to another
      computer.</para>

    <para>This section will explain how to use floppy disks in
      FreeBSD.  It will primarily cover formatting and usage of
      3.5inch DOS floppies, but the concepts are similar for other
      floppy disk formats.</para>

    <sect2>
      <title>Formatting Floppies</title>

      <sect3>
	<title>The Device</title>

	<para>Floppy disks are accessed through entries in
	  <filename>/dev</filename>, just like other devices.  To
	  access the raw floppy disk, simply use
	  <filename>/dev/fdN</filename>.</para>
      </sect3>

      <sect3>
	<title>Formatting</title>

	<para>A floppy disk needs to be low-level formated before it
	  can be used.  This is usually done by the vendor, but
	  formatting is a good way to check media integrity.  Although
	  it is possible to force larger (or smaller) disk sizes,
	  1440kB is what most floppy disks are designed for.</para>

	<para>To low-level format the floppy disk you need to use
	  &man.fdformat.1;.  This utility expects the device name as an
	  argument.</para>

	  <para>Make note of any error messages, as these can help
	    determine if the disk is good or bad.</para>

	<sect4>
	  <title>Formatting Floppy Disks</title>

	  <para>Use the
	    <filename>/dev/fdN</filename>
	    devices to format the floppy.  Insert a new 3.5inch floppy
	    disk in your drive and issue:</para>

	  <screen>&prompt.root; <userinput>/usr/sbin/fdformat -f 1440 /dev/fd0</userinput></screen>

	</sect4>
      </sect3>
    </sect2>

    <sect2>
      <title>The Disk Label</title>

      <para>After low-level formatting the disk, you will need to
	place a disk label on it.  This disk label will be destroyed
	later, but it is needed by the system to determine the size of
	the disk and its geometry later.</para>

      <para>The new disk label will take over the whole disk, and will
	contain all the proper information about the geometry of the
	floppy.  The geometry values for the disk label are listed in
	<filename>/etc/disktab</filename>.</para>

      <para>You can run now &man.bsdlabel.8; like so:</para>

      <screen>&prompt.root; <userinput>/sbin/bsdlabel -B -r -w /dev/fd0 fd1440</userinput></screen>

    </sect2>

    <sect2>
      <title>The File System</title>

      <para>Now the floppy is ready to be high-level formated. This
	will place a new file system on it, which will let FreeBSD read
	and write to the disk.  After creating the new file system, the
	disk label is destroyed, so if you want to reformat the disk, you
	will have to recreate the disk label.</para>

      <para>The floppy's file system can be either UFS or FAT.
	 FAT is generally a better choice for floppies.</para>

      <para>To put a new file system on the floppy, issue:</para>

      <screen>&prompt.root; <userinput>/sbin/newfs_msdos /dev/fd0</userinput></screen>

      <para>The disk is now ready for use.</para>
    </sect2>


    <sect2>
      <title>Using the Floppy</title>

      <para>To use the floppy, mount it with &man.mount.msdosfs.8;.  One can also use
	<package>emulators/mtools</package> from the ports
	collection.</para>
    </sect2>
  </sect1>

  <sect1 xml:id="backups-tapebackups">
    <title>Creating and Using Data Tapes</title>

    <indexterm><primary>tape media</primary></indexterm>
    <para>The major tape media are the 4mm, 8mm, QIC, mini-cartridge and
      DLT.</para>

    <sect2 xml:id="backups-tapebackups-4mm">
      <title>4mm (DDS: Digital Data Storage)</title>

      <indexterm>
        <primary>tape media</primary>
	<secondary>DDS (4mm) tapes</secondary>
      </indexterm>
      <indexterm>
        <primary>tape media</primary>
	<secondary>QIC tapes</secondary>
      </indexterm>
      <para>4mm tapes are replacing QIC as the workstation backup media of
	choice.  This trend accelerated greatly when Conner purchased Archive,
	a leading manufacturer of QIC drives, and then stopped production of
	QIC drives.  4mm drives are small and quiet but do not have the
	reputation for reliability that is enjoyed by 8mm drives.  The
	cartridges are less expensive and smaller (3 x 2 x 0.5 inches, 76 x 51
	x 12 mm) than 8mm cartridges.  4mm, like 8mm, has comparatively short
	head life for the same reason, both use helical scan.</para>

      <para>Data throughput on these drives starts ~150&nbsp;kB/s, peaking at ~500&nbsp;kB/s.
	Data capacity starts at 1.3&nbsp;GB and ends at 2.0&nbsp;GB.  Hardware
	compression, available with most of these drives, approximately
	doubles the capacity.  Multi-drive tape library units can have 6
	drives in a single cabinet with automatic tape changing.  Library
	capacities reach 240&nbsp;GB.</para>

      <para>The DDS-3 standard now supports tape capacities up to 12&nbsp;GB (or
	24&nbsp;GB compressed).</para>

      <para>4mm drives, like 8mm drives, use helical-scan.  All the benefits
	and drawbacks of helical-scan apply to both 4mm and 8mm drives.</para>

      <para>Tapes should be retired from use after 2,000 passes or 100 full
	backups.</para>
    </sect2>

    <sect2 xml:id="backups-tapebackups-8mm">
      <title>8mm (Exabyte)</title>
      <indexterm>
        <primary>tape media</primary>
	<secondary>Exabyte (8mm) tapes</secondary>
      </indexterm>

      <para>8mm tapes are the most common SCSI tape drives; they are the best
	choice of exchanging tapes.  Nearly every site has an Exabyte 2&nbsp;GB 8mm
	tape drive.  8mm drives are reliable, convenient and quiet. Cartridges
	are inexpensive and small (4.8 x 3.3 x 0.6 inches; 122 x 84 x 15 mm).
	One downside of 8mm tape is relatively short head and tape life due to
	the high rate of relative motion of the tape across the heads.</para>

      <para>Data throughput ranges from ~250&nbsp;kB/s to ~500&nbsp;kB/s.  Data sizes start
	at 300&nbsp;MB and go up to 7&nbsp;GB.  Hardware compression, available with
	most of these drives, approximately doubles the capacity.  These
	drives are available as single units or multi-drive tape libraries
	with 6 drives and 120 tapes in a single cabinet.  Tapes are changed
	automatically by the unit.  Library capacities reach 840+&nbsp;GB.</para>

      <para>The Exabyte <quote>Mammoth</quote> model supports 12&nbsp;GB on one tape
	(24&nbsp;GB with compression) and costs approximately twice as much as
	conventional tape drives.</para>

      <para>Data is recorded onto the tape using helical-scan, the heads are
	positioned at an angle to the media (approximately 6 degrees).  The
	tape wraps around 270 degrees of the spool that holds the heads.  The
	spool spins while the tape slides over the spool.  The result is a
	high density of data and closely packed tracks that angle across the
	tape from one edge to the other.</para>
    </sect2>

    <sect2 xml:id="backups-tapebackups-qic">
      <title>QIC</title>
      <indexterm>
        <primary>tape media</primary>
	<secondary>QIC-150</secondary>
      </indexterm>

      <para>QIC-150 tapes and drives are, perhaps, the most common tape drive
	and media around.  QIC tape drives are the least expensive <quote>serious</quote>
	backup drives.  The downside is the cost of media.  QIC tapes are
	expensive compared to 8mm or 4mm tapes, up to 5 times the price per GB
	data storage.  But, if your needs can be satisfied with a half-dozen
	tapes, QIC may be the correct choice.  QIC is the
	<emphasis>most</emphasis> common tape drive.  Every site has a QIC
	drive of some density or another.  Therein lies the rub, QIC has a
	large number of densities on physically similar (sometimes identical)
	tapes.  QIC drives are not quiet.  These drives audibly seek before
	they begin to record data and are clearly audible whenever reading,
	writing or seeking.  QIC tapes measure 6&nbsp;x 4&nbsp;x 0.7 inches
	(152&nbsp;x 102&nbsp;x 17 mm).</para>

      <para>Data throughput ranges from ~150&nbsp;kB/s to ~500&nbsp;kB/s.  Data capacity
	ranges from 40&nbsp;MB to 15&nbsp;GB.  Hardware compression is available on many
	of the newer QIC drives.  QIC drives are less frequently installed;
	they are being supplanted by DAT drives.</para>

      <para>Data is recorded onto the tape in tracks.  The tracks run along
	the long axis of the tape media from one end to the other.  The number
	of tracks, and therefore the width of a track, varies with the tape's
	capacity.  Most if not all newer drives provide backward-compatibility
	at least for reading (but often also for writing).  QIC has a good
	reputation regarding the safety of the data (the mechanics are simpler
	and more robust than for helical scan drives).</para>

      <para>Tapes should be retired from use after 5,000 backups.</para>
    </sect2>

    <sect2 xml:id="backups-tapebackups-dlt">
      <title>DLT</title>
      <indexterm>
        <primary>tape media</primary>
	<secondary>DLT</secondary>
      </indexterm>

      <para>DLT has the fastest data transfer rate of all the drive types
	listed here.  The 1/2" (12.5mm) tape is contained in a single spool
	cartridge (4 x 4 x 1 inches; 100 x 100 x 25 mm).  The cartridge has a
	swinging gate along one entire side of the cartridge.  The drive
	mechanism opens this gate to extract the tape leader.  The tape leader
	has an oval hole in it which the drive uses to <quote>hook</quote> the tape.  The
	take-up spool is located inside the tape drive.  All the other tape
	cartridges listed here (9 track tapes are the only exception) have
	both the supply and take-up spools located inside the tape cartridge
	itself.</para>

      <para>Data throughput is approximately 1.5&nbsp;MB/s, three times the throughput of
	4mm, 8mm, or QIC tape drives.  Data capacities range from 10&nbsp;GB to 20&nbsp;GB
	for a single drive.  Drives are available in both multi-tape changers
	and multi-tape, multi-drive tape libraries containing from 5 to 900
	tapes over 1 to 20 drives, providing from 50&nbsp;GB to 9&nbsp;TB of
	storage.</para>

      <para>With compression, DLT Type IV format supports up to 70&nbsp;GB
	capacity.</para>

      <para>Data is recorded onto the tape in tracks parallel to the direction
	of travel (just like QIC tapes).  Two tracks are written at once.
	Read/write head lifetimes are relatively long; once the tape stops
	moving, there is no relative motion between the heads and the
	tape.</para>
    </sect2>

    <sect2>
      <title xml:id="backups-tapebackups-ait">AIT</title>
      <indexterm>
        <primary>tape media</primary>
	<secondary>AIT</secondary>
      </indexterm>

      <para>AIT is a new format from Sony, and can hold up to 50&nbsp;GB (with
	compression) per tape.  The tapes contain memory chips which retain an
	index of the tape's contents.  This index can be rapidly read by the
	tape drive to determine the position of files on the tape, instead of
	the several minutes that would be required for other tapes.  Software
	such as <application>SAMS:Alexandria</application> can operate forty or more AIT tape libraries,
	communicating directly with the tape's memory chip to display the
	contents on screen, determine what files were backed up to which
	tape, locate the correct tape, load it, and restore the data from the
	tape.</para>

      <para>Libraries like this cost in the region of $20,000, pricing them a
	little out of the hobbyist market.</para>
    </sect2>

    <sect2>
      <title>Using a New Tape for the First Time</title>

      <para>The first time that you try to read or write a new, completely
	blank tape, the operation will fail.  The console messages should be
	similar to:</para>

      <screen>sa0(ncr1:4:0): NOT READY asc:4,1
sa0(ncr1:4:0):  Logical unit is in process of becoming ready</screen>

      <para>The tape does not contain an Identifier Block (block number 0).
	All QIC tape drives since the adoption of QIC-525 standard write an
	Identifier Block to the tape.  There are two solutions:</para>

      <itemizedlist>
	<listitem>
	  <para><command>mt fsf 1</command> causes the tape drive to write an
	  Identifier Block to the tape.</para>
	</listitem>

	<listitem>
	  <para>Use the front panel button to eject the tape.</para>

	  <para>Re-insert the tape and <command>dump</command> data to
	    the tape.</para>

	  <para><command>dump</command> will report <errorname>DUMP: End of tape
	    detected</errorname> and the console will show: <errorname>HARDWARE
	    FAILURE info:280 asc:80,96</errorname>.</para>

	  <para>rewind the tape using: <command>mt rewind</command>.</para>

	  <para>Subsequent tape operations are successful.</para>
	</listitem>
      </itemizedlist>

    </sect2>
  </sect1>

  <sect1 xml:id="backups-floppybackups">
    <title>Backups to Floppies</title>

    <sect2 xml:id="floppies-using">
      <title>Can I Use Floppies for Backing Up My Data?</title>
      <indexterm><primary>backup floppies</primary></indexterm>
      <indexterm><primary>floppy disks</primary></indexterm>

      <para>Floppy disks are not really a suitable media for
        making backups as:</para>

      <itemizedlist>
	<listitem>
	  <para>The media is unreliable, especially over long periods of
	    time.</para>
	</listitem>

	<listitem>
	  <para>Backing up and restoring is very slow.</para>
	</listitem>

	<listitem>
	  <para>They have a very limited capacity (the days of backing up
	    an entire hard disk onto a dozen or so floppies has long since
	    passed).</para>
	</listitem>
      </itemizedlist>

      <para>However, if you have no other method of backing up your data then
	floppy disks are better than no backup at all.</para>

      <para>If you do have to use floppy disks then ensure that you use good
	quality ones. Floppies that have been lying around the office for a
	couple of years are a bad choice. Ideally use new ones from a
	reputable manufacturer.</para>
    </sect2>

    <sect2 xml:id="floppies-creating">
      <title>So How Do I Backup My Data to Floppies?</title>

      <para>The best way to backup to floppy disk is to use
	&man.tar.1; with the <option>-M</option> (multi
	volume) option, which allows backups to span multiple
	floppies.</para>

      <para>To backup all the files in the current directory and sub-directory
	use this (as <systemitem class="username">root</systemitem>):</para>

      <screen>&prompt.root; <userinput>tar Mcvf /dev/fd0 *</userinput></screen>

      <para>When the first floppy is full &man.tar.1; will prompt you to
	insert the next volume (because &man.tar.1; is media independent it
	refers to volumes; in this context it means floppy disk).</para>

      <screen>Prepare volume #2 for /dev/fd0 and hit return:</screen>

      <para>This is repeated (with the volume number incrementing) until all
	the specified files have been archived.</para>
    </sect2>

    <sect2 xml:id="floppies-compress">
      <title>Can I Compress My Backups?</title>
      <indexterm>
        <primary><command>tar</command></primary>
      </indexterm>
      <indexterm>
        <primary><command>gzip</command></primary>
      </indexterm>
      <indexterm><primary>compression</primary></indexterm>

      <para>Unfortunately, &man.tar.1; will not allow the
	<option>-z</option> option to be used for multi-volume archives.
	You could, of course, &man.gzip.1; all the files,
	&man.tar.1; them to the floppies, then
	&man.gunzip.1; the files again!</para>
    </sect2>

    <sect2 xml:id="floppies-restoring">
      <title>How Do I Restore My Backups?</title>

      <para>To restore the entire archive use:</para>

      <screen>&prompt.root; <userinput>tar Mxvf /dev/fd0</userinput></screen>

      <para>There are two ways that you can use to restore only
	specific files.  First, you can start with the first floppy
	and use:</para>

      <screen>&prompt.root; <userinput>tar Mxvf /dev/fd0 filename</userinput></screen>

      <para>The utility &man.tar.1; will prompt you to insert subsequent floppies until it
	finds the required file.</para>

      <para>Alternatively, if you know which floppy the file is on then you
	can simply insert that floppy and use the same command as above. Note
	that if the first file on the floppy is a continuation from the
	previous one then &man.tar.1; will warn you that it cannot
	restore it, even if you have not asked it to!</para>
    </sect2>
  </sect1>

  <sect1 xml:id="backup-strategies">
    <info><title>Backup Strategies</title>
      <authorgroup>
	<author><personname><firstname>Lowell</firstname><surname>Gilbert</surname></personname><contrib>Original work by </contrib></author>
      </authorgroup>
      
    </info>

    

    <para>The first requirement in devising a backup plan is to make sure that
      all of the following problems are covered:</para>

    <itemizedlist>
      <listitem>
	<para>Disk failure</para>
      </listitem>
      <listitem>
	<para>Accidental file deletion</para>
      </listitem>
      <listitem>
	<para>Random file corruption</para>
      </listitem>
      <listitem>
	<para>Complete machine destruction (e.g. fire), including destruction
	  of any on-site backups.</para>
      </listitem>
    </itemizedlist>

    <para>It is perfectly possible that some systems will be best served by
      having each of these problems covered by a completely different
      technique.  Except for strictly personal systems with very low-value
      data, it is unlikely that one technique would cover all of them.</para>

    <para>Some of the techniques in the toolbox are:</para>

    <itemizedlist>
      <listitem>
	<para>Archives of the whole system, backed up onto permanent media
	  offsite.  This actually provides protection against all of the
	  possible problems listed above, but is slow and inconvenient to
	  restore from.  You can keep copies of the backups onsite and/or
	  online, but there will still be inconveniences in restoring files,
	  especially for non-privileged users.</para>
      </listitem>

      <listitem>
	<para>Filesystem snapshots.  This is really only helpful in the
	  accidental file deletion scenario, but it can be
	  <emphasis>very</emphasis> helpful in that case, and is quick and
	  easy to deal with.</para>
      </listitem>

      <listitem>
	<para>Copies of whole filesystems and/or disks (e.g. periodic &man.rsync.1; of
	  the whole machine).  This is generally most useful in networks with
	  unique requirements.  For general protection against disk failure,
	  it is usually inferior to <acronym>RAID</acronym>.  For restoring
	  accidentally deleted files, it can be comparable to
	  <acronym>UFS</acronym> snapshots, but that depends on your
	  preferences.</para>
      </listitem>

      <listitem>
	<para><acronym>RAID</acronym>.  Minimizes or avoids downtime when a
	  disk fails.  At the expense of having to deal with disk failures
	  more often (because you have more disks), albeit at a much lower
	  urgency.</para>
      </listitem>

      <listitem>
	<para>Checking fingerprints of files.  The &man.mtree.8; utility is
	  very useful for this.  Although it is not a backup technique, it
	  helps guarantee that you will notice when you need to resort to your
	  backups.  This is particularly important for offline backups, and
	  should be checked periodically.</para>
      </listitem>
    </itemizedlist>

    <para>It is quite easy to come up with even more techniques, many of them
      variations on the ones listed above.  Specialized requirements will
      usually lead to specialized techniques (for example, backing up a live
      database usually requires a method particular to the database software
      as an intermediate step).  The important thing is to know what dangers
      you want to protect against, and how you will handle each.</para>
  </sect1>

  <sect1 xml:id="backup-basics">
    <title>Backup Basics</title>

    <para>The three major backup programs are
	&man.dump.8;,
	&man.tar.1;,
      and
	&man.cpio.1;.</para>

    <sect2>
      <title>Dump and Restore</title>
      <indexterm>
        <primary>backup software</primary>
	<secondary>dump / restore</secondary>
      </indexterm>
      <indexterm><primary><command>dump</command></primary></indexterm>
      <indexterm><primary><command>restore</command></primary></indexterm>

      <para>The traditional &unix; backup programs are
	<command>dump</command> and <command>restore</command>.  They
	operate on the drive as a collection of disk blocks, below the
	abstractions of files, links and directories that are created by
	the file systems. <command>dump</command> backs up an entire
	file system on a device.  It is unable to backup only part of a
	file system or a directory tree that spans more than one
	file system.  <command>dump</command> does not write files and
	directories to tape, but rather writes the raw data blocks that
	comprise files and directories.</para>

      <note><para>If you use <command>dump</command> on your root directory, you
        would not back up <filename>/home</filename>,
        <filename>/usr</filename> or many other directories since
        these are typically mount points for other file systems or
        symbolic links into those file systems.</para></note>

      <para><command>dump</command> has quirks that remain from its early days in
	Version 6 of AT&amp;T UNIX (circa 1975).  The default
	parameters are suitable for 9-track tapes (6250 bpi), not the
	high-density media available today (up to 62,182 ftpi).  These
	defaults must be overridden on the command line to utilize the
	capacity of current tape drives.</para>

      <indexterm><primary><filename>.rhosts</filename></primary></indexterm>
      <para>It is also possible to backup data across the network to a
        tape drive attached to another computer with <command>rdump</command> and
        <command>rrestore</command>.  Both programs rely upon &man.rcmd.3; and
        &man.ruserok.3; to access the remote tape drive.  Therefore,
	the user performing the backup must be listed in the
	<filename>.rhosts</filename> file on the remote computer.  The
        arguments to <command>rdump</command> and <command>rrestore</command> must be suitable
        to use on the remote computer.  When
        <command>rdump</command>ing from a FreeBSD computer to an
        Exabyte tape drive connected to a Sun called
        <systemitem>komodo</systemitem>, use:</para>

      <screen>&prompt.root; <userinput>/sbin/rdump 0dsbfu 54000 13000 126 komodo:/dev/nsa8 /dev/da0a 2&gt;&amp;1</userinput></screen>

      <para>Beware: there are security implications to
        allowing <filename>.rhosts</filename> authentication.  Evaluate your
        situation carefully.</para>

      <para>It is also possible to use <command>dump</command> and
        <command>restore</command> in a more secure fashion over
        <command>ssh</command>.</para>

      <example>
	<title>Using <command>dump</command> over <application>ssh</application></title>

	<screen>&prompt.root; <userinput>/sbin/dump -0uan -f - /usr | gzip -2 | ssh -c blowfish \
          targetuser@targetmachine.example.com dd of=/mybigfiles/dump-usr-l0.gz</userinput></screen>

      </example>

      <para>Or using <command>dump</command>'s built-in method,
        setting the environment variable <envar>RSH</envar>:</para>

      <example>
	<title>Using <command>dump</command> over <application>ssh</application> with <envar>RSH</envar> set</title>

	<screen>&prompt.root; <userinput>RSH=/usr/bin/ssh /sbin/dump -0uan -f targetuser@targetmachine.example.com:/dev/sa0 /usr</userinput></screen>

      </example>

    </sect2>

    <sect2>
      <title><command>tar</command></title>
      <indexterm>
        <primary>backup software</primary>
        <secondary><command>tar</command></secondary>
      </indexterm>

      <para>&man.tar.1; also dates back to Version 6 of AT&amp;T UNIX
	(circa 1975).  <command>tar</command> operates in cooperation
	with the file system; it writes files and
	directories to tape. <command>tar</command> does not support the
	full range of options that are available from &man.cpio.1;, but
	it does not require the unusual command
	pipeline that <command>cpio</command> uses.</para>

      <indexterm><primary><command>tar</command></primary></indexterm>

      <para>On FreeBSD 5.3 and later, both GNU <command>tar</command>
        and the default <command>bsdtar</command> are available.  The
        GNU version can be invoked with <command>gtar</command>.  It
        supports remote devices using the same syntax as
        <command>rdump</command>.  To <command>tar</command> to an
        Exabyte tape drive connected to a Sun called
        <systemitem>komodo</systemitem>, use:</para>

      <screen>&prompt.root; <userinput>/usr/bin/gtar cf komodo:/dev/nsa8 . 2&gt;&amp;1</userinput></screen>

      <para>The same could be accomplished with
	<command>bsdtar</command> by using a pipeline and
	<command>rsh</command> to send the data to a remote tape
	drive.</para>

      <screen>&prompt.root; <userinput>tar cf - . | rsh hostname dd of=tape-device obs=20b</userinput></screen>

      <para>If you are worried about the security of backing up over a
	network you should use the <command>ssh</command> command
	instead of <command>rsh</command>.</para>
    </sect2>

    <sect2>
      <title><command>cpio</command></title>
      <indexterm>
        <primary>backup software</primary>
        <secondary><command>cpio</command></secondary>
      </indexterm>

      <para>&man.cpio.1; is the original &unix; file interchange tape
	program for magnetic media.  <command>cpio</command> has options
	(among many others) to perform byte-swapping, write a number of
	different archive formats, and pipe the data to other programs.
	This last feature makes <command>cpio</command> an excellent
	choice for installation media.  <command>cpio</command> does not
	know how to walk the directory tree and a list of files must be
	provided through <filename>stdin</filename>.</para>
      <indexterm><primary><command>cpio</command></primary></indexterm>

      <para><command>cpio</command> does not support backups across
	the network.  You can use a pipeline and <command>rsh</command>
	to send the data to a remote tape drive.</para>

      <screen>&prompt.root; <userinput>for f in directory_list; do</userinput>
<userinput>find $f &gt;&gt; backup.list</userinput>
<userinput>done</userinput>
&prompt.root; <userinput>cpio -v -o --format=newc &lt; backup.list | ssh user@host "cat &gt; backup_device"</userinput></screen>

      <para>Where <replaceable>directory_list</replaceable> is the list of
	directories you want to back up,
	<replaceable>user</replaceable>@<replaceable>host</replaceable> is the
	user/hostname combination that will be performing the backups, and
	<replaceable>backup_device</replaceable> is where the backups should
	be written to (e.g., <filename>/dev/nsa0</filename>).</para>
    </sect2>

    <sect2>
      <title><command>pax</command></title>
      <indexterm>
        <primary>backup software</primary>
        <secondary><command>pax</command></secondary>
      </indexterm>
      <indexterm><primary><command>pax</command></primary></indexterm>
      <indexterm><primary>POSIX</primary></indexterm>
      <indexterm><primary>IEEE</primary></indexterm>

      <para>&man.pax.1; is IEEE/&posix;'s answer to
	<command>tar</command> and <command>cpio</command>.  Over the
	years the various versions of <command>tar</command> and
	<command>cpio</command> have gotten slightly incompatible.  So
	rather than fight it out to fully standardize them, &posix;
	created a new archive utility. <command>pax</command> attempts
	to read and write many of the various <command>cpio</command>
	and <command>tar</command> formats, plus new formats of its own.
	Its command set more resembles <command>cpio</command> than
	<command>tar</command>.</para>
    </sect2>

    <sect2 xml:id="backups-programs-amanda">
      <title><application>Amanda</application></title>
      <indexterm>
        <primary>backup software</primary>
        <secondary><application>Amanda</application></secondary>
      </indexterm>
      <indexterm><primary><application>Amanda</application></primary></indexterm>

      <!-- Remove link until <port> tag is available -->
      <para><application>Amanda</application> (Advanced Maryland
        Network Disk Archiver) is a client/server backup system,
        rather than a single program.  An <application>Amanda</application> server will backup to
        a single tape drive any number of computers that have <application>Amanda</application>
        clients and a network connection to the <application>Amanda</application> server.  A
        common problem at sites with a number of large disks is
        that the length of time required to backup to data directly to tape
        exceeds the amount of time available for the task.  <application>Amanda</application>
        solves this problem.  <application>Amanda</application> can use a <quote>holding disk</quote> to
        backup several file systems at the same time.  <application>Amanda</application> creates
        <quote>archive sets</quote>: a group of tapes used over a period of time to
        create full backups of all the file systems listed in <application>Amanda</application>'s
        configuration file.  The <quote>archive set</quote> also contains nightly
        incremental (or differential) backups of all the file systems.
        Restoring a damaged file system requires the most recent full
        backup and the incremental backups.</para>

      <para>The configuration file provides fine control of backups and the
	network traffic that <application>Amanda</application> generates.  <application>Amanda</application> will use any of the
	above backup programs to write the data to tape.  <application>Amanda</application> is available
	as either a port or a package, it is not installed by default.</para>
      </sect2>

    <sect2>
      <title>Do Nothing</title>

      <para><quote>Do nothing</quote> is not a computer program, but it is the
	most widely used backup strategy.  There are no initial costs.  There
	is no backup schedule to follow.  Just say no.  If something happens
	to your data, grin and bear it!</para>

      <para>If your time and your data is worth little to nothing, then
	<quote>Do nothing</quote> is the most suitable backup program for your
	computer.  But beware, &unix; is a useful tool, you may find that within
	six months you have a collection of files that are valuable to
	you.</para>

      <para><quote>Do nothing</quote> is the correct backup method for
	<filename>/usr/obj</filename> and other directory trees that can be
	exactly recreated by your computer.  An example is the files that
	comprise the HTML or &postscript; version of this Handbook.
	These document formats have been created from SGML input
	files.  Creating backups of the HTML or &postscript; files is
	not necessary.  The SGML files are backed up regularly.</para>
    </sect2>

    <sect2>
      <title>Which Backup Program Is Best?</title>
      <indexterm>
        <primary>LISA</primary>
      </indexterm>

      <para>&man.dump.8; <emphasis>Period.</emphasis> Elizabeth D. Zwicky
	torture tested all the backup programs discussed here.  The clear
	choice for preserving all your data and all the peculiarities of &unix;
	file systems is <command>dump</command>.  Elizabeth created file systems containing
	a large variety of unusual conditions (and some not so unusual ones)
	and tested each program by doing a backup and restore of those
	file systems.  The peculiarities included: files with holes, files with
	holes and a block of nulls, files with funny characters in their
	names, unreadable and unwritable files, devices, files that change
	size during the backup, files that are created/deleted during the
	backup and more.  She presented the results at LISA V in Oct. 1991.
	See <link xlink:href="http://berdmann.dyndns.org/zwicky/testdump.doc.html">torture-testing
	  Backup and Archive Programs</link>.</para>
    </sect2>

    <sect2>
      <title>Emergency Restore Procedure</title>

      <sect3>
	<title>Before the Disaster</title>

	<para>There are only four steps that you need to perform in
	  preparation for any disaster that may occur.</para>
	<indexterm>
    <primary><command>bsdlabel</command></primary>
  </indexterm>

	<para>First, print the bsdlabel from each of your disks
	  (e.g. <command>bsdlabel da0 | lpr</command>), your file system table
	  (<filename>/etc/fstab</filename>) and all boot messages,
	  two copies of
	  each.</para>

	<indexterm><primary>fix-it floppies</primary></indexterm>
	<para>Second, determine that the boot and fix-it floppies
	  (<filename>boot.flp</filename> and <filename>fixit.flp</filename>)
	  have all your devices.  The easiest way to check is to reboot your
	  machine with the boot floppy in the floppy drive and check the boot
	  messages.  If all your devices are listed and functional, skip on to
	  step three.</para>

	<para>Otherwise, you have to create two custom bootable
	  floppies which have a kernel that can mount all of your disks
	  and access your tape drive.  These floppies must contain:
	  <command>fdisk</command>, <command>bsdlabel</command>,
	  <command>newfs</command>, <command>mount</command>, and
	  whichever backup program you use.  These programs must be
	  statically linked.  If you use <command>dump</command>, the
	  floppy must contain <command>restore</command>.</para>

	<para>Third, create backup tapes regularly.  Any changes that you make
	  after your last backup may be irretrievably lost.  Write-protect the
	  backup tapes.</para>

	<para>Fourth, test the floppies (either <filename>boot.flp</filename>
	  and <filename>fixit.flp</filename> or the two custom bootable
	  floppies you made in step two.) and backup tapes.  Make notes of the
	  procedure.  Store these notes with the bootable floppy, the
	  printouts and the backup tapes.  You will be so distraught when
	  restoring that the notes may prevent you from destroying your backup
	  tapes (How? In place of <command>tar xvf /dev/sa0</command>, you
	  might accidentally type <command>tar cvf /dev/sa0</command> and
	  over-write your backup tape).</para>

	<para>For an added measure of security, make bootable floppies and two
	  backup tapes each time.  Store one of each at a remote location.  A
	  remote location is NOT the basement of the same office building.  A
	  number of firms in the World Trade Center learned this lesson the
	  hard way.  A remote location should be physically separated from
	  your computers and disk drives by a significant distance.</para>

	<example>
	  <title>A Script for Creating a Bootable Floppy</title>

	<programlisting><![CDATA[#!/bin/sh
#
# create a restore floppy
#
# format the floppy
#
PATH=/bin:/sbin:/usr/sbin:/usr/bin

fdformat -q fd0
if [ $? -ne 0 ]
then
	 echo "Bad floppy, please use a new one"
	 exit 1
fi

# place boot blocks on the floppy
#
bsdlabel -w -B /dev/fd0c fd1440

#
# newfs the one and only partition
#
newfs -t 2 -u 18 -l 1 -c 40 -i 5120 -m 5 -o space /dev/fd0a

#
# mount the new floppy
#
mount /dev/fd0a /mnt

#
# create required directories
#
mkdir /mnt/dev
mkdir /mnt/bin
mkdir /mnt/sbin
mkdir /mnt/etc
mkdir /mnt/root
mkdir /mnt/mnt			# for the root partition
mkdir /mnt/tmp
mkdir /mnt/var

#
# populate the directories
#
if [ ! -x /sys/compile/MINI/kernel ]
then
	 cat &lt;&lt; EOM
The MINI kernel does not exist, please create one.
Here is an example config file:
#
# MINI - A kernel to get FreeBSD onto a disk.
#
machine         "i386"
cpu             "I486_CPU"
ident           MINI
maxusers        5

options         INET                    # needed for _tcp _icmpstat _ipstat
                                        #            _udpstat _tcpstat _udb
options         FFS                     #Berkeley Fast File System
options         FAT_CURSOR              #block cursor in syscons or pccons
options         SCSI_DELAY=15           #Be pessimistic about Joe SCSI device
options         NCONS=2                 #1 virtual consoles
options         USERCONFIG              #Allow user configuration with -c XXX

config          kernel	root on da0 swap on da0 and da1 dumps on da0

device          isa0
device          pci0

device          fdc0	at isa? port "IO_FD1" bio irq 6 drq 2 vector fdintr
device          fd0	at fdc0 drive 0

device          ncr0

device          scbus0

device          sc0	at isa? port "IO_KBD" tty irq 1 vector scintr
device          npx0	at isa? port "IO_NPX" irq 13 vector npxintr

device          da0
device          da1
device          da2

device          sa0

pseudo-device   loop            # required by INET
pseudo-device   gzip            # Exec gzipped a.out's
EOM
	 exit 1
fi

cp -f /sys/compile/MINI/kernel /mnt

gzip -c -best /sbin/init > /mnt/sbin/init
gzip -c -best /sbin/fsck > /mnt/sbin/fsck
gzip -c -best /sbin/mount > /mnt/sbin/mount
gzip -c -best /sbin/halt > /mnt/sbin/halt
gzip -c -best /sbin/restore > /mnt/sbin/restore

gzip -c -best /bin/sh > /mnt/bin/sh
gzip -c -best /bin/sync > /mnt/bin/sync

cp /root/.profile /mnt/root

cp -f /dev/MAKEDEV /mnt/dev
chmod 755 /mnt/dev/MAKEDEV

chmod 500 /mnt/sbin/init
chmod 555 /mnt/sbin/fsck /mnt/sbin/mount /mnt/sbin/halt
chmod 555 /mnt/bin/sh /mnt/bin/sync
chmod 6555 /mnt/sbin/restore

#
# create the devices nodes
#
cd /mnt/dev
./MAKEDEV std
./MAKEDEV da0
./MAKEDEV da1
./MAKEDEV da2
./MAKEDEV sa0
./MAKEDEV pty0
cd /

#
# create minimum file system table
#
cat > /mnt/etc/fstab &lt;&lt;EOM
/dev/fd0a    /    ufs    rw  1  1
EOM

#
# create minimum passwd file
#
cat > /mnt/etc/passwd &lt;&lt;EOM
root:*:0:0:Charlie &amp;:/root:/bin/sh
EOM

cat > /mnt/etc/master.passwd &lt;&lt;EOM
root::0:0::0:0:Charlie &amp;:/root:/bin/sh
EOM

chmod 600 /mnt/etc/master.passwd
chmod 644 /mnt/etc/passwd
/usr/sbin/pwd_mkdb -d/mnt/etc /mnt/etc/master.passwd

#
# umount the floppy and inform the user
#
/sbin/umount /mnt
echo "The floppy has been unmounted and is now ready."]]></programlisting>

        </example>

      </sect3>

      <sect3>
	<title>After the Disaster</title>

	<para>The key question is: did your hardware survive?  You have been
	  doing regular backups so there is no need to worry about the
	  software.</para>

	<para>If the hardware has been damaged, the parts should be replaced
	  before attempting to use the computer.</para>

	<para>If your hardware is okay, check your floppies.  If you are using
	  a custom boot floppy, boot single-user (type <literal>-s</literal>
	  at the <prompt>boot:</prompt> prompt).  Skip the following
	  paragraph.</para>

	<para>If you are using the <filename>boot.flp</filename> and
	  <filename>fixit.flp</filename> floppies, keep reading.  Insert the
	  <filename>boot.flp</filename> floppy in the first floppy drive and
	  boot the computer.  The original install menu will be displayed on
	  the screen.  Select the <literal>Fixit--Repair mode with CDROM or
	    floppy.</literal> option.  Insert the
	  <filename>fixit.flp</filename> when prompted.
	  <command>restore</command> and the other programs that you need are
	  located in <filename>/mnt2/rescue</filename>
	  (<filename>/mnt2/stand</filename> for
	  &os; versions older than 5.2).</para>

	<para>Recover each file system separately.</para>

	<indexterm>
    <primary><command>mount</command></primary>
  </indexterm>
	<indexterm><primary>root partition</primary></indexterm>
	<indexterm>
    <primary><command>bsdlabel</command></primary>
  </indexterm>
	<indexterm>
    <primary><command>newfs</command></primary>
  </indexterm>
	<para>Try to <command>mount</command> (e.g. <command>mount /dev/da0a
	    /mnt</command>)  the root partition of your first disk.  If the
	  bsdlabel was damaged, use <command>bsdlabel</command> to re-partition and
	  label the disk to match the label that you printed and saved.  Use
	    <command>newfs</command> to re-create the file systems.  Re-mount the root
	  partition of the floppy read-write (<command>mount -u -o rw
	    /mnt</command>).  Use your backup program and backup tapes to
	  recover the data for this file system (e.g. <command>restore vrf
	    /dev/sa0</command>).  Unmount the file system (e.g. <command>umount
	    /mnt</command>). Repeat for each file system that was
	  damaged.</para>

	<para>Once your system is running, backup your data onto new tapes.
	  Whatever caused the crash or data loss may strike again.  Another
	  hour spent now may save you from further distress later.</para>
      </sect3>
    </sect2>
  </sect1>

  <sect1 xml:id="disks-virtual">
    <info><title>Network, Memory, and File-Backed File Systems</title>
      <authorgroup>
	<author><personname><firstname>Marc</firstname><surname>Fonvieille</surname></personname><contrib>Reorganized and enhanced by </contrib></author>
      </authorgroup>
    </info>
    
    <indexterm><primary>virtual disks</primary></indexterm>
    <indexterm>
      <primary>disks</primary>
      <secondary>virtual</secondary>
    </indexterm>

    <para>Aside from the disks you physically insert into your computer:
      floppies, CDs, hard drives, and so forth; other forms of disks
      are understood by FreeBSD - the <firstterm>virtual
      disks</firstterm>.</para>

    <indexterm><primary>NFS</primary></indexterm>
    <indexterm><primary>Coda</primary></indexterm>
    <indexterm>
      <primary>disks</primary>
      <secondary>memory</secondary>
    </indexterm>
    <para>These include network file systems such as the <link linkend="network-nfs">Network File System</link> and Coda, memory-based
      file systems and
      file-backed file systems.</para>

    <para>According to the FreeBSD version you run, you will have to use
      different tools for creation and use of file-backed and
      memory-based file systems.</para>

    <note>
      <para>Use &man.devfs.5; to allocate device nodes transparently for the
	user.</para>
    </note>

    <sect2 xml:id="disks-mdconfig">
      <title>File-Backed File System</title>
      <indexterm>
        <primary>disks</primary>
        <secondary>file-backed</secondary>
      </indexterm>

      <para>The utility &man.mdconfig.8; is used to configure and enable
	memory disks, &man.md.4;, under FreeBSD.  To use
	&man.mdconfig.8;, you have to load &man.md.4; module or to add
	the support in your kernel configuration file:</para>

      <programlisting>device md</programlisting>

      <para>The &man.mdconfig.8; command supports three kinds of
	memory backed virtual disks: memory disks allocated with
	&man.malloc.9;, memory disks using a file or swap space as
	backing.  One possible use is the mounting of floppy
	or CD images kept in files.</para>

      <para>To mount an existing file system image:</para>

      <example>
	<title>Using <command>mdconfig</command> to Mount an Existing File System
	  Image</title>

	<screen>&prompt.root; <userinput>mdconfig -a -t vnode -f diskimage -u 0</userinput>
&prompt.root; <userinput>mount /dev/md0 /mnt</userinput></screen>
      </example>

      <para>To create a new file system image with &man.mdconfig.8;:</para>

      <example>
	<title>Creating a New File-Backed Disk with <command>mdconfig</command></title>

	<screen>&prompt.root; <userinput>dd if=/dev/zero of=newimage bs=1k count=5k</userinput>
5120+0 records in
5120+0 records out
&prompt.root; <userinput>mdconfig -a -t vnode -f newimage -u 0</userinput>
&prompt.root; <userinput>bsdlabel -w md0 auto</userinput>
&prompt.root; <userinput>newfs md0a</userinput>
/dev/md0a: 5.0MB (10224 sectors) block size 16384, fragment size 2048
        using 4 cylinder groups of 1.25MB, 80 blks, 192 inodes.
super-block backups (for fsck -b #) at:
 160, 2720, 5280, 7840
&prompt.root; <userinput>mount /dev/md0a /mnt</userinput>
&prompt.root; <userinput>df /mnt</userinput>
Filesystem 1K-blocks Used Avail Capacity  Mounted on
/dev/md0a       4710    4  4330     0%    /mnt</screen>
      </example>

      <para>If you do not specify the unit number with the
	<option>-u</option> option, &man.mdconfig.8; will use the
	&man.md.4; automatic allocation to select an unused device.
	The name of the allocated unit will be output on stdout like
	<filename>md4</filename>.  For more details about
	&man.mdconfig.8;, please refer to the manual page.</para>

      <para>The utility &man.mdconfig.8; is very useful, however it
	asks many command lines to create a file-backed file system.
	FreeBSD also comes with a tool called &man.mdmfs.8;,
	this program configures a &man.md.4; disk using
	&man.mdconfig.8;, puts a UFS file system on it using
	&man.newfs.8;, and mounts it using &man.mount.8;.  For example,
	if you want to create and mount the same file system image as
	above, simply type the following:</para>

      <example>
	<title>Configure and Mount a File-Backed Disk with <command>mdmfs</command></title>
	<screen>&prompt.root; <userinput>dd if=/dev/zero of=newimage bs=1k count=5k</userinput>
5120+0 records in
5120+0 records out
&prompt.root; <userinput>mdmfs -F newimage -s 5m md0 /mnt</userinput>
&prompt.root; <userinput>df /mnt</userinput>
Filesystem 1K-blocks Used Avail Capacity  Mounted on
/dev/md0        4718    4  4338     0%    /mnt</screen>
      </example>

      <para>If you use the option <option>md</option> without unit
	number, &man.mdmfs.8; will use &man.md.4; auto-unit feature to
	automatically select an unused device.  For more details
	about &man.mdmfs.8;, please refer to the manual page.</para>

    </sect2>

    <sect2 xml:id="disks-md-freebsd5">
      <title>Memory-Based File System</title>
      <indexterm>
        <primary>disks</primary>
        <secondary>memory file system</secondary>
      </indexterm>

      <para>For a
	memory-based file system the <quote>swap backing</quote>
	should normally be used.  Using swap backing does not mean
	that the memory disk will be swapped out to disk by default,
	but merely that the memory disk will be allocated from a
	memory pool which can be swapped out to disk if needed.  It is
	also possible to create memory-based disk which are
	&man.malloc.9; backed, but using malloc backed memory disks,
	especially large ones, can result in a system panic if the
	kernel runs out of memory.</para>

      <example>
	<title>Creating a New Memory-Based Disk with
	  <command>mdconfig</command></title>

	<screen>&prompt.root; <userinput>mdconfig -a -t swap -s 5m -u 1</userinput>
&prompt.root; <userinput>newfs -U md1</userinput>
/dev/md1: 5.0MB (10240 sectors) block size 16384, fragment size 2048
        using 4 cylinder groups of 1.27MB, 81 blks, 192 inodes.
        with soft updates
super-block backups (for fsck -b #) at:
 160, 2752, 5344, 7936
&prompt.root; <userinput>mount /dev/md1 /mnt</userinput>
&prompt.root; <userinput>df /mnt</userinput>
Filesystem 1K-blocks Used Avail Capacity  Mounted on
/dev/md1        4718    4  4338     0%    /mnt</screen>
      </example>

      <example>
	<title>Creating a New Memory-Based Disk with
	  <command>mdmfs</command></title>
	<screen>&prompt.root; <userinput>mdmfs -s 5m md2 /mnt</userinput>
&prompt.root; <userinput>df /mnt</userinput>
Filesystem 1K-blocks Used Avail Capacity  Mounted on
/dev/md2        4846    2  4458     0%    /mnt</screen>
      </example>
    </sect2>

    <sect2>
      <title>Detaching a Memory Disk from the System</title>
      <indexterm>
        <primary>disks</primary>
        <secondary>detaching a memory disk</secondary>
      </indexterm>

      <para>When a memory-based or file-based file system
	is not used, you should release all resources to the system.
	The first thing to do is to unmount the file system, then use
	&man.mdconfig.8; to detach the disk from the system and release
	the resources.</para>

      <para>For example to detach and free all resources used by
	<filename>/dev/md4</filename>:</para>

      <screen>&prompt.root; <userinput>mdconfig -d -u 4</userinput></screen>

      <para>It is possible to list information about configured
	&man.md.4; devices in using the command <command>mdconfig
	-l</command>.</para>
    </sect2>
  </sect1>

  <sect1 xml:id="snapshots">
    <info><title>File System Snapshots</title>
      <authorgroup>
	<author><personname><firstname>Tom</firstname><surname>Rhodes</surname></personname><contrib>Contributed by </contrib></author>
      </authorgroup>
      
    </info>

    

    <indexterm>
      <primary>file systems</primary>
      <secondary>snapshots</secondary>
    </indexterm>

      <para>FreeBSD offers a feature in conjunction with
	<link linkend="soft-updates">Soft Updates</link>: File system snapshots.</para>

      <para>Snapshots allow a user to create images of specified file
	systems, and treat them as a file.
	Snapshot files must be created in the file system that the
	action is performed on, and a user may create no more than 20
	snapshots per file system.  Active snapshots are recorded
	in the superblock so they are persistent across unmount and
	remount operations along with system reboots.  When a snapshot
	is no longer required, it can be removed with the standard &man.rm.1;
	command.  Snapshots may be removed in any order,
	however all the used space may not be acquired because another snapshot will
	possibly claim some of the released blocks.</para>

      <para>The un-alterable <option>snapshot</option> file flag is set
      by &man.mksnap.ffs.8; after initial creation of a snapshot file.
	The &man.unlink.1; command makes an exception for snapshot files
	since it allows them to be removed.</para>

      <para>Snapshots are created with the &man.mount.8; command.  To place
	a snapshot of <filename>/var</filename> in the file
	<filename>/var/snapshot/snap</filename> use the following
	command:</para>

<screen>&prompt.root; <userinput>mount -u -o snapshot /var/snapshot/snap /var</userinput></screen>

      <para>Alternatively, you can use &man.mksnap.ffs.8; to create
	a snapshot:</para>
<screen>&prompt.root; <userinput>mksnap_ffs /var /var/snapshot/snap</userinput></screen>

      <para>One can find snapshot files on a file system (e.g. <filename>/var</filename>)
        by using the &man.find.1; command:</para>
<screen>&prompt.root; <userinput>find /var -flags snapshot</userinput></screen>

      <para>Once a snapshot has been created, it has several
	uses:</para>

      <itemizedlist>
	<listitem>
	  <para>Some administrators will use a snapshot file for backup purposes,
	    because the snapshot can be transfered to CDs or tape.</para>
	</listitem>

	<listitem>
	  <para>The file system integrity checker, &man.fsck.8;, may be run on the snapshot.
	    Assuming that the file system was clean when it was mounted, you
	    should always get a clean (and unchanging) result.
	    This is essentially what the
	    background &man.fsck.8; process does.</para>
	</listitem>

	<listitem>
	  <para>Run the &man.dump.8; utility on the snapshot.
	    A dump will be returned that is consistent with the
	    file system and the timestamp of the snapshot.  &man.dump.8;
	    can also take a snapshot, create a dump image and then
	    remove the snapshot in one command using the
	    <option>-L</option> flag.</para>
	</listitem>

	<listitem>
	  <para>&man.mount.8; the snapshot as a frozen image of the file system.
	    To &man.mount.8; the snapshot
	    <filename>/var/snapshot/snap</filename> run:</para>

<screen>&prompt.root; <userinput>mdconfig -a -t vnode -f /var/snapshot/snap -u 4</userinput>
&prompt.root; <userinput>mount -r /dev/md4 /mnt</userinput></screen>

	</listitem>
      </itemizedlist>

      <para>You can now walk the hierarchy of your frozen <filename>/var</filename>
	file system mounted at <filename>/mnt</filename>.  Everything will
	initially be in the same state it was during the snapshot creation time.
	The only exception is that any earlier snapshots will appear
	as zero length files.  When the use of a snapshot has delimited,
	it can be unmounted with:</para>

<screen>&prompt.root; <userinput>umount /mnt</userinput>
&prompt.root; <userinput>mdconfig -d -u 4</userinput></screen>

      <para>For more information about <option>softupdates</option> and
	file system snapshots, including technical papers, you can visit
	Marshall Kirk McKusick's website at
	<uri xlink:href="http://www.mckusick.com/">http://www.mckusick.com/</uri>.</para>
  </sect1>

  <sect1 xml:id="quotas">
    <title>File System Quotas</title>
    <indexterm>
      <primary>accounting</primary>
      <secondary>disk space</secondary>
    </indexterm>
    <indexterm><primary>disk quotas</primary></indexterm>

    <para>Quotas are an optional feature of the operating system that
      allow you to limit the amount of disk space and/or the number of
      files a user or members of a group may allocate on a per-file
      system basis. This is used most often on timesharing systems where
      it is desirable to limit the amount of resources any one user or
      group of users may allocate.  This will prevent one user or group
      of users from consuming all of the available disk space.</para>

    <sect2>
      <title>Configuring Your System to Enable Disk Quotas</title>

      <para>Before attempting to use disk quotas, it is necessary to make
	sure that quotas are configured in your kernel.  This is done by
	adding the following line to your kernel configuration
	file:</para>

      <programlisting>options QUOTA</programlisting>

      <para>The stock <filename>GENERIC</filename> kernel does not have
	this enabled by default, so you will have to configure, build and
	install a custom kernel in order to use disk quotas.  Please refer
	to <xref linkend="kernelconfig"/> for more information on kernel
	configuration.</para>

      <para>Next you will need to enable disk quotas in
	<filename>/etc/rc.conf</filename>.  This is done by adding the
	line:</para>

      <programlisting>enable_quotas="YES"</programlisting>
      <indexterm>
        <primary>disk quotas</primary>
        <secondary>checking</secondary>
      </indexterm>
      <para>For finer control over your quota startup, there is an
	additional configuration variable available. Normally on bootup,
	the quota integrity of each file system is checked by the
	&man.quotacheck.8; program.  The
	&man.quotacheck.8; facility insures that the data in
	the quota database properly reflects the data on the file system.
	This is a very time consuming process that will significantly
	affect the time your system takes to boot. If you would like to
	skip this step, a variable in <filename>/etc/rc.conf</filename>
	is made available for the purpose:</para>

      <programlisting>check_quotas="NO"</programlisting>

      <para>Finally you will need to edit <filename>/etc/fstab</filename>
	to enable disk quotas on a per-file system basis.  This is where
	you can either enable user or group quotas or both for all of your
	file systems.</para>

      <para>To enable per-user quotas on a file system, add the
	<option>userquota</option> option to the options field in the
	<filename>/etc/fstab</filename> entry for the file system you want
	to enable quotas on.  For example:</para>

      <programlisting>/dev/da1s2g   /home    ufs rw,userquota 1 2</programlisting>

      <para>Similarly, to enable group quotas, use the
	<option>groupquota</option> option instead of
	<option>userquota</option>.  To enable both user and
	group quotas, change the entry as follows:</para>

      <programlisting>/dev/da1s2g    /home    ufs rw,userquota,groupquota 1 2</programlisting>

      <para>By default, the quota files are stored in the root directory of
	the file system with the names <filename>quota.user</filename> and
	<filename>quota.group</filename> for user and group quotas
	respectively.  See &man.fstab.5; for more
	information.  Even though the &man.fstab.5; manual page says that
	you can specify
	an alternate location for the quota files, this is not recommended
	because the various quota utilities do not seem to handle this
	properly.</para>

      <para>At this point you should reboot your system with your new
	kernel.  <filename>/etc/rc</filename> will automatically run the
	appropriate commands to  create the initial quota files for all of
	the quotas you enabled in <filename>/etc/fstab</filename>, so
	there is no need to manually create any zero length quota
	files.</para>

      <para>In the normal course of operations you should not be required
	to run the &man.quotacheck.8;,
	&man.quotaon.8;, or &man.quotaoff.8;
	commands manually.  However, you may want to read their manual pages
	just to be familiar with their operation.</para>
    </sect2>

    <sect2>
      <title>Setting Quota Limits</title>
      <indexterm>
        <primary>disk quotas</primary>
        <secondary>limits</secondary>
      </indexterm>

      <para>Once you have configured your system to enable quotas, verify
	that they really are enabled.  An easy way to do this is to
	run:</para>

      <screen>&prompt.root; <userinput>quota -v</userinput></screen>

      <para>You should see a one line summary of disk usage and current
	quota limits for each file system that quotas are enabled
	on.</para>

      <para>You are now ready to start assigning quota limits with the
	&man.edquota.8; command.</para>

      <para>You have several options on how to enforce limits on the
	amount of disk space a user or group may allocate, and how many
	files they may create.  You may limit allocations based on disk
	space (block quotas) or number of files (inode quotas) or a
	combination of both.  Each of these limits are further broken down
	into two categories: hard and soft limits.</para>

      <indexterm><primary>hard limit</primary></indexterm>
      <para>A hard limit may not be exceeded.  Once a user reaches his
	hard limit he may not make any further allocations on the file
	system in question.  For example, if the user has a hard limit of
	500 kbytes on a file system and is currently using 490 kbytes, the
	user can only allocate an additional 10 kbytes.  Attempting to
	allocate an additional 11 kbytes will fail.</para>

      <indexterm><primary>soft limit</primary></indexterm>
      <para>Soft limits, on the other hand, can be exceeded for a limited
	amount of time.  This period of time is known as the grace period,
	which is one week by default.  If a user stays over his or her
	soft limit longer than the grace period, the soft limit will
	turn into a hard limit and no further allocations will be allowed.
	When the user drops back below the soft limit, the grace period
	will be reset.</para>

      <para>The following is an example of what you might see when you run
	the &man.edquota.8; command.  When the
	&man.edquota.8; command is invoked, you are placed into
	the editor specified by the <envar>EDITOR</envar> environment
	variable, or in the <application>vi</application> editor if the
	<envar>EDITOR</envar> variable is not set, to allow you to edit
	the quota limits.</para>

      <screen>&prompt.root; <userinput>edquota -u test</userinput></screen>

      <programlisting>Quotas for user test:
/usr: kbytes in use: 65, limits (soft = 50, hard = 75)
        inodes in use: 7, limits (soft = 50, hard = 60)
/usr/var: kbytes in use: 0, limits (soft = 50, hard = 75)
        inodes in use: 0, limits (soft = 50, hard = 60)</programlisting>

      <para>You will normally see two lines for each file system that has
	quotas enabled.  One line for the block limits, and one line for
	inode limits.  Simply change the value you want updated to modify
	the quota limit.  For example, to raise this user's block limit
	from a soft limit of 50 and a hard limit of 75 to a soft limit of
	500 and a hard limit of 600, change:</para>

      <programlisting>/usr: kbytes in use: 65, limits (soft = 50, hard = 75)</programlisting>

      <para>to:</para>

      <programlisting>/usr: kbytes in use: 65, limits (soft = 500, hard = 600)</programlisting>

      <para>The new quota limits will be in place when you exit the
	editor.</para>

      <para>Sometimes it is desirable to set quota limits on a range of
	UIDs.  This can be done by use of the <option>-p</option> option
	on the &man.edquota.8; command.  First, assign the
	desired quota limit to a user, and then run
	<command>edquota -p protouser startuid-enduid</command>.  For
	example, if user <systemitem class="username">test</systemitem> has the desired quota
	limits, the following command can be used to duplicate those quota
	limits for UIDs 10,000 through 19,999:</para>

      <screen>&prompt.root; <userinput>edquota -p test 10000-19999</userinput></screen>

      <para>For more information see &man.edquota.8; manual page.</para>
    </sect2>

    <sect2>
      <title>Checking Quota Limits and Disk Usage</title>
      <indexterm>
        <primary>disk quotas</primary>
        <secondary>checking</secondary>
      </indexterm>

      <para>You can use either the &man.quota.1; or the
	&man.repquota.8; commands to check quota limits and
	disk usage.  The &man.quota.1; command can be used to
	check individual user or group quotas and disk usage.  A user
	may only examine his own quota, and the quota of a group he
	is a member of. Only the super-user may view all user and group
	quotas.  The
	&man.repquota.8; command can be used to get a summary
	of all quotas and disk usage for file systems with quotas
	enabled.</para>

      <para>The following is some sample output from the
	<command>quota -v</command> command for a user that has quota
	limits on two file systems.</para>

      <programlisting>Disk quotas for user test (uid 1002):
     Filesystem  usage    quota   limit   grace   files   quota   limit   grace
           /usr      65*     50      75   5days       7      50      60
       /usr/var       0      50      75               0      50      60</programlisting>

      <indexterm><primary>grace period</primary></indexterm>
      <para>On the <filename>/usr</filename> file system in the above
	example, this user is currently 15 kbytes over the soft limit of
	50 kbytes and has 5 days of the grace period left.  Note the
	asterisk <literal>*</literal> which indicates that the user is
	currently over his quota limit.</para>

      <para>Normally file systems that the user is not using any disk
	space on will not show up in the output from the
	&man.quota.1; command, even if he has a quota limit
	assigned for that file system.  The <option>-v</option> option
	will display those file systems, such as the
	<filename>/usr/var</filename> file system in the above
	example.</para>
    </sect2>

    <sect2>
      <title>Quotas over NFS</title>
      <indexterm><primary>NFS</primary></indexterm>

      <para>Quotas are enforced by the quota subsystem on the NFS server.
	The &man.rpc.rquotad.8; daemon makes quota information available
	to the &man.quota.1; command on NFS clients, allowing users on
	those machines to see their quota statistics.</para>

      <para>Enable <command>rpc.rquotad</command> in
	<filename>/etc/inetd.conf</filename> like so:</para>

      <programlisting>rquotad/1      dgram rpc/udp wait root /usr/libexec/rpc.rquotad rpc.rquotad</programlisting>

      <para>Now restart <command>inetd</command>:</para>

      <screen>&prompt.root; <userinput>kill -HUP `cat /var/run/inetd.pid`</userinput></screen>
    </sect2>
  </sect1>


  <sect1 xml:id="disks-encrypting">
    <info><title>Encrypting Disk Partitions</title>
      <authorgroup>
	<author><personname><firstname>Lucky</firstname><surname>Green</surname></personname><contrib>Contributed by </contrib><affiliation>
	    <address><email>shamrock@cypherpunks.to</email></address>
	  </affiliation></author>
      </authorgroup>
      
    </info>

    
    <indexterm>
      <primary>disks</primary>
      <secondary>encrypting</secondary></indexterm>

    <para>FreeBSD offers excellent online protections against
      unauthorized data access.  File permissions and Mandatory
      Access Control (MAC) (see <xref linkend="mac"/>) help prevent
      unauthorized third-parties from accessing data while the operating
      system is active and the computer is powered up.  However,
      the permissions enforced by the operating system are irrelevant if an
      attacker has physical access to a computer and can simply move
      the computer's hard drive to another system to copy and analyze
      the sensitive data.</para>

    <para>Regardless of how an attacker may have come into possession of
      a hard drive or powered-down computer, both <application>GEOM
      Based Disk Encryption (gbde)</application> and
      <command>geli</command> cryptographic subsystems in &os; are able
      to protect the data on the computer's file systems against even
      highly-motivated attackers with significant resources. Unlike
      cumbersome encryption methods that encrypt only individual files,
      <command>gbde</command> and <command>geli</command> transparently
      encrypt entire file systems.  No cleartext ever touches the hard
      drive's platter.</para>

    <sect2>
      <title>Disk Encryption with <application>gbde</application></title>

      <procedure>
	<step>
	  <title>Become <systemitem class="username">root</systemitem></title>

	  <para>Configuring <application>gbde</application> requires
	    super-user privileges.</para>

	  <screen>&prompt.user; <userinput>su -</userinput>
Password:</screen>
	</step>

	<step>
	  <title>Add &man.gbde.4; Support to the Kernel Configuration File</title>

	  <para>Add the following line to the kernel configuration
	    file:</para>

	  <para><literal>options GEOM_BDE</literal></para>

	  <para>Rebuild the kernel as described in <xref linkend="kernelconfig"/>.</para>

	  <para>Reboot into the new kernel.</para>
	</step>

        <step>
          <para>An alternative to recompiling the kernel is to use
            <command>kldload</command> to load &man.gbde.4;:</para>

          <screen>&prompt.root; <userinput>kldload geom_bde</userinput></screen>
        </step>
      </procedure>

    <sect3>
      <title>Preparing the Encrypted Hard Drive</title>

      <para>The following example assumes that you are adding a new hard
	drive to your system that will hold a single encrypted partition.
	This partition will be mounted as <filename>/private</filename>.
	<application>gbde</application> can also be used to encrypt
	<filename>/home</filename> and <filename>/var/mail</filename>, but
	this requires more complex instructions which exceed the scope of
	this introduction.</para>

      <procedure>
	<step>
	  <title>Add the New Hard Drive</title>

	  <para>Install the new drive to the system as explained in <xref linkend="disks-adding"/>. For the purposes of this example,
	    a new hard drive partition has been added as
	    <filename>/dev/ad4s1c</filename>.  The
	    <filename>/dev/ad0s1*</filename>
	    devices represent existing standard FreeBSD partitions on
	    the example system.</para>

	  <screen>&prompt.root; <userinput>ls /dev/ad*</userinput>
/dev/ad0        /dev/ad0s1b     /dev/ad0s1e     /dev/ad4s1
/dev/ad0s1      /dev/ad0s1c     /dev/ad0s1f     /dev/ad4s1c
/dev/ad0s1a     /dev/ad0s1d     /dev/ad4</screen>
	</step>

	<step>
	  <title>Create a Directory to Hold gbde Lock Files</title>

	  <screen>&prompt.root; <userinput>mkdir /etc/gbde</userinput></screen>

	  <para>The <application>gbde</application> lock file contains
	    information that <application>gbde</application> requires to
	    access encrypted partitions. Without access to the lock file,
	    <application>gbde</application> will not be able to decrypt
	    the data contained in the encrypted partition without
	    significant manual intervention which is not supported by the
	    software. Each encrypted partition uses a separate lock
	    file.</para>
	</step>

	<step>
	  <title>Initialize the gbde Partition</title>

	  <para>A <application>gbde</application> partition must be
	    initialized before it can be used. This initialization needs to
	    be performed only once:</para>

	  <screen>&prompt.root; <userinput>gbde init /dev/ad4s1c -i -L /etc/gbde/ad4s1c</userinput></screen>

	  <para>&man.gbde.8; will open your editor, permitting you to set
	    various configuration options in a template. For use with UFS1
	    or UFS2, set the sector_size to 2048:</para>

	  <programlisting>$<!-- This is not the space you are looking
for-->FreeBSD: src/sbin/gbde/template.txt,v 1.1 2002/10/20 11:16:13 phk Exp $
#
# Sector size is the smallest unit of data which can be read or written.
# Making it too small decreases performance and decreases available space.
# Making it too large may prevent filesystems from working.  512 is the
# minimum and always safe.  For UFS, use the fragment size
#
sector_size     =       2048
[...]
</programlisting>

	  <para>&man.gbde.8; will ask you twice to type the passphrase that
	    should be used to secure the data. The passphrase must be the
	    same both times. <application>gbde</application>'s ability to
	    protect your data depends entirely on the quality of the
	    passphrase that you choose.
	  <footnote>
          <para>For tips on how to select a secure passphrase that is easy
	    to remember, see the <link xlink:href="http://world.std.com/~reinhold/diceware.html">Diceware
	    Passphrase</link> website.</para></footnote></para>

	  <para>The <command>gbde init</command> command creates a lock
	    file for your <application>gbde</application> partition that in
	    this example is stored as
	    <filename>/etc/gbde/ad4s1c</filename>.</para>

	  <caution>
	    <para><application>gbde</application> lock files
	      <emphasis>must</emphasis> be backed up together with the
	      contents of any encrypted partitions. While deleting a lock
	      file alone cannot prevent a determined attacker from
	      decrypting a <application>gbde</application> partition,
	      without the lock file, the legitimate owner will be unable
	      to access the data on the encrypted partition without a
	      significant amount of work that is totally unsupported by
	      &man.gbde.8; and its designer.</para>
	  </caution>
	</step>

	<step>
	  <title>Attach the Encrypted Partition to the Kernel</title>

	  <screen>&prompt.root; <userinput>gbde attach /dev/ad4s1c -l /etc/gbde/ad4s1c</userinput></screen>

	  <para> You will be asked to provide the passphrase that you
	    selected during the initialization of the encrypted partition.
	    The new encrypted device will show up in
	    <filename>/dev</filename> as
	    <filename>/dev/device_name.bde</filename>:</para>

	  <screen>&prompt.root; <userinput>ls /dev/ad*</userinput>
/dev/ad0        /dev/ad0s1b     /dev/ad0s1e     /dev/ad4s1
/dev/ad0s1      /dev/ad0s1c     /dev/ad0s1f     /dev/ad4s1c
/dev/ad0s1a     /dev/ad0s1d     /dev/ad4        /dev/ad4s1c.bde</screen>
	</step>

	<step>
	  <title>Create a File System on the Encrypted Device</title>

	  <para>Once the encrypted device has been attached to the kernel,
	    you can create a file system on the device. To create a file
	    system on the encrypted device, use &man.newfs.8;. Since it is
	    much faster to initialize a new UFS2 file system than it is to
	    initialize the old UFS1 file system, using &man.newfs.8; with
	    the <option>-O2</option> option is recommended.</para>

	  <screen>&prompt.root; <userinput>newfs -U -O2 /dev/ad4s1c.bde</userinput></screen>

	  <note>
	    <para>The &man.newfs.8; command must be performed on an
	      attached <application>gbde</application> partition which
	      is identified by a
	      <filename>*.bde</filename>
	      extension to the device name.</para>
	  </note>
	</step>

	<step>
	  <title>Mount the Encrypted Partition</title>

	  <para>Create a mount point for the encrypted file system.</para>

	  <screen>&prompt.root; <userinput>mkdir /private</userinput></screen>

	  <para>Mount the encrypted file system.</para>

	  <screen>&prompt.root; <userinput>mount /dev/ad4s1c.bde /private</userinput></screen>
	</step>

	<step>
	  <title>Verify That the Encrypted File System is Available</title>

	  <para>The encrypted file system should now be visible to
	    &man.df.1; and be available for use.</para>

	  <screen>&prompt.user; <userinput>df -H</userinput>
Filesystem        Size   Used  Avail Capacity  Mounted on
/dev/ad0s1a      1037M    72M   883M     8%    /
/devfs            1.0K   1.0K     0B   100%    /dev
/dev/ad0s1f       8.1G    55K   7.5G     0%    /home
/dev/ad0s1e      1037M   1.1M   953M     0%    /tmp
/dev/ad0s1d       6.1G   1.9G   3.7G    35%    /usr
/dev/ad4s1c.bde   150G   4.1K   138G     0%    /private</screen>
	</step>
      </procedure>
    </sect3>

    <sect3>
      <title>Mounting Existing Encrypted File Systems</title>

      <para>After each boot, any encrypted file systems must be
	re-attached to the kernel, checked for errors, and mounted, before
	the file systems can be used. The required commands must be
	executed as user <systemitem class="username">root</systemitem>.</para>

      <procedure>
	<step>
	  <title>Attach the gbde Partition to the Kernel</title>

	  <screen>&prompt.root; <userinput>gbde attach /dev/ad4s1c -l /etc/gbde/ad4s1c</userinput></screen>

	  <para>You will be asked to provide the passphrase that you
	    selected during initialization of the encrypted
	    <application>gbde</application> partition.</para>
	</step>

	<step>
	  <title>Check the File System for Errors</title>

	  <para>Since encrypted file systems cannot yet be listed in
	    <filename>/etc/fstab</filename> for automatic mounting, the
	    file systems must be checked for errors by running &man.fsck.8;
	    manually before mounting.</para>

	  <screen>&prompt.root; <userinput>fsck -p -t ffs /dev/ad4s1c.bde</userinput></screen>
	</step>

	<step>
	  <title>Mount the Encrypted File System</title>

	  <screen>&prompt.root; <userinput>mount /dev/ad4s1c.bde /private</userinput></screen>

	  <para>The encrypted file system is now available for use.</para>
	</step>
      </procedure>

      <sect4>
	<title>Automatically Mounting Encrypted Partitions</title>

	<para>It is possible to create a script to automatically attach,
	  check, and mount an encrypted partition, but for security reasons
	  the script should not contain the &man.gbde.8; password.  Instead,
	  it is recommended that such scripts be run manually while
	  providing the password via the console or &man.ssh.1;.</para>

	<para>As an alternative, an <filename>rc.d</filename> script is
	  provided.  Arguments for this script can be passed via
	  &man.rc.conf.5;, for example:</para>

	<screen>gbde_autoattach_all="YES"
gbde_devices="ad4s1c"</screen>

	<para>This will require that the <application>gbde</application>
	  passphrase be entered at boot time.  After typing the correct
	  passphrase, the <application>gbde</application> encrypted
	  partition will be mounted automatically.  This can be very
	  useful when using <application>gbde</application> on
	  notebooks.</para>
      </sect4>
    </sect3>

      <sect3>
	<title>Cryptographic Protections Employed by gbde</title>

	<para>&man.gbde.8; encrypts the sector payload using 128-bit AES in
	  CBC mode.  Each sector on the disk is encrypted with a different
	  AES key. For more information on <application>gbde</application>'s
	  cryptographic design, including how the sector keys are derived
	  from the user-supplied passphrase, see &man.gbde.4;.</para>
      </sect3>

      <sect3>
	<title>Compatibility Issues</title>

	<para>&man.sysinstall.8; is incompatible with
	  <application>gbde</application>-encrypted devices. All
	  <filename>*.bde</filename> devices must be detached from the
	  kernel before starting &man.sysinstall.8; or it will crash during
	  its initial probing for devices. To detach the encrypted device
	  used in our example, use the following command:</para>
	<screen>&prompt.root; <userinput>gbde detach /dev/ad4s1c</userinput></screen>

      <para>Also note that, as &man.vinum.4; does not use the
	&man.geom.4; subsystem, you cannot use
	<application>gbde</application> with
	<application>vinum</application> volumes.</para>
      </sect3>

    </sect2>

    <sect2>
      <info><title>Disk Encryption with <command>geli</command></title>
	<authorgroup>
	  <author><personname><firstname>Daniel</firstname><surname>Gerzo</surname></personname><contrib>Contributed by </contrib></author>
	</authorgroup>
	
      </info>

      

      <para>A new cryptographic GEOM class is available as of &os; 6.0 -
	<command>geli</command>.  It is currently being developed by
	&a.pjd;.  <command>Geli</command> is different to
	<command>gbde</command>; it offers different features and uses
	a different scheme for doing cryptographic work.</para>

      <para>The most important features of &man.geli.8; are:</para>

      <itemizedlist>
	<listitem>
	  <para>Utilizes the &man.crypto.9; framework &mdash; when
	    cryptographic hardware is available, <command>geli</command>
	    will use it automatically.</para>
	</listitem>
	<listitem>
	  <para>Supports multiple cryptographic algorithms (currently
	     AES, Blowfish, and 3DES).</para>
	</listitem>
	<listitem>
	  <para>Allows the root partition to be encrypted.  The
	    passphrase used to access the encrypted root partition will
	    be requested during the system boot.</para>
	</listitem>
	<listitem>
	  <para>Allows the use of two independent keys (e.g. a
	    <quote>key</quote> and a <quote>company key</quote>).</para>
	</listitem>
	<listitem>
	  <para><command>geli</command> is fast - performs simple
	    sector-to-sector encryption.</para>
	</listitem>
	<listitem>
	  <para>Allows backup and restore of Master Keys.  When a user
	    has to destroy his keys, it will be possible to get access
	    to the data again by restoring keys from the backup.</para>
	</listitem>
	<listitem>
	  <para>Allows to attach a disk with a random, one-time key
	    &mdash; useful for swap partitions and temporary file
	    systems.</para>
	</listitem>
      </itemizedlist>

      <para>More <command>geli</command> features can be found in the
	&man.geli.8; manual page.</para>

      <para>The next steps will describe how to enable support for
	<command>geli</command> in the &os; kernel and will explain how
	to create a new <command>geli</command> encryption provider.  At
	the end it will be demonstrated how to create an encrypted swap
	partition using features provided by <command>geli</command>.</para>

      <para>In order to use <command>geli</command>, you must be running
	&os; 6.0-RELEASE or later.  Super-user privileges will be
	required since modifications to the kernel are necessary.</para>

      <procedure>
	<step>
	  <title>Adding <command>geli</command> Support to the Kernel
	    Configuration File</title>

	  <para>Add the following lines to the kernel configuration
	    file:</para>

	  <screen>options GEOM_ELI
device crypto</screen>

	  <para>Rebuild the kernel as described in <xref linkend="kernelconfig"/>.</para>

	  <para>Alternatively, the <command>geli</command> module can
	    be loaded at boot time.  Add the following line to the
	    <filename>/boot/loader.conf</filename>:</para>

	  <para><literal>geom_eli_load="YES"</literal></para>

	  <para>&man.geli.8; should now be supported by the kernel.</para>
	</step>

	<step>
	  <title>Generating the Master Key</title>

	  <para>The following example will describe how to generate a
	    key file, which will be used as part of the Master Key for
	    the encrypted provider mounted under
	    <filename>/private</filename>.  The key
	    file will provide some random data used to encrypt the
	    Master Key.  The Master Key will be protected by a
	    passphrase as well.  Provider's sector size will be 4kB big.
	    Furthermore, the discussion will describe how to attach the
	    <command>geli</command> provider, create a file system on
	    it, how to mount it, how to work with it, and finally how to
	    detach it.</para>

	  <para>It is recommended to use a bigger sector size (like 4kB) for
	    better performance.</para>

	  <para>The Master Key will be protected with a passphrase and
	    the data source for key file will be
	    <filename>/dev/random</filename>.  The sector size of
	    <filename>/dev/da2.eli</filename>, which we call provider,
	    will be 4kB.</para>

	  <screen>&prompt.root; <userinput>dd if=/dev/random of=/root/da2.key bs=64 count=1</userinput>
&prompt.root; <userinput>geli init -s 4096 -K /root/da2.key /dev/da2</userinput>
Enter new passphrase:
Reenter new passphrase:</screen>

	  <para>It is not mandatory that both a passphrase and a key
	    file are used; either method of securing the Master Key can
	    be used in isolation.</para>

	  <para>If key file is given as <quote>-</quote>, standard
	    input will be used.  This example shows how more than one
	    key file can be used.</para>

	  <screen>&prompt.root; <userinput>cat keyfile1 keyfile2 keyfile3 | geli init -K - /dev/da2</userinput></screen>
	</step>

	<step>
	  <title>Attaching the Provider with the generated Key</title>

	  <screen>&prompt.root; <userinput>geli attach -k /root/da2.key /dev/da2</userinput>
Enter passphrase:</screen>

	  <para>The new plaintext device will be named
	    <filename>/dev/da2.eli</filename>.</para>

	  <screen>&prompt.root; <userinput>ls /dev/da2*</userinput>
/dev/da2  /dev/da2.eli</screen>
	</step>

	<step>
	  <title>Creating the new File System</title>

	  <screen>&prompt.root; <userinput>dd if=/dev/random of=/dev/da2.eli bs=1m</userinput>
&prompt.root; <userinput>newfs /dev/da2.eli</userinput>
&prompt.root; <userinput>mount /dev/da2.eli /private</userinput></screen>

	<para>The encrypted file system should be visible to &man.df.1;
	  and be available for use now.</para>

	  <screen>&prompt.root; <userinput>df -H</userinput>
Filesystem     Size   Used  Avail Capacity  Mounted on
/dev/ad0s1a    248M    89M   139M    38%    /
/devfs         1.0K   1.0K     0B   100%    /dev
/dev/ad0s1f    7.7G   2.3G   4.9G    32%    /usr
/dev/ad0s1d    989M   1.5M   909M     0%    /tmp
/dev/ad0s1e    3.9G   1.3G   2.3G    35%    /var
/dev/da2.eli   150G   4.1K   138G     0%    /private</screen>

	</step>

	<step>
	  <title>Unmounting and Detaching the Provider</title>

	  <para>Once the work on the encrypted partition is done, and
	    the <filename>/private</filename> partition
	    is no longer needed, it is prudent to consider unmounting
	    and detaching the <command>geli</command> encrypted
	    partition from the kernel.</para>

	  <screen>&prompt.root; <userinput>umount /private</userinput>
&prompt.root; <userinput>geli detach da2.eli</userinput></screen>
	</step>
      </procedure>

      <para>More information about the use of &man.geli.8; can be
        found in the manual page.</para>

      <sect3>
	<title>Using the <filename>geli</filename> <filename>rc.d</filename> Script</title>

	<para><command>geli</command> comes with a <filename>rc.d</filename> script which
	  can be used to simplify the usage of <command>geli</command>.
	  An example of configuring <command>geli</command> through
	  &man.rc.conf.5; follows:</para>

	<screen>geli_devices="da2"
geli_da2_flags="-p -k /root/da2.key"</screen>

	<para>This will configure <filename>/dev/da2</filename> as a
	  <command>geli</command> provider of which the Master Key file
	  is located in <filename>/root/da2.key</filename>, and
	  <command>geli</command> will not use a passphrase when
	  attaching the provider (note that this can only be used if -P
	  was given during the <command>geli</command> init phase).  The
	  system will detach the <command>geli</command> provider from
	  the kernel before the system shuts down.</para>

	<para>More information about configuring <filename>rc.d</filename> is provided in the
	  <link linkend="configtuning-rcd">rc.d</link> section of the
	  Handbook.</para>
      </sect3>
    </sect2>
  </sect1>


  <sect1 xml:id="swap-encrypting">
    <info><title>Encrypting Swap Space</title>
      <authorgroup>
	<author><personname><firstname>Christian</firstname><surname>Br&uuml;ffer</surname></personname><contrib>Written by </contrib></author>
      </authorgroup>
    </info>

    
    <indexterm>
      <primary>swap</primary>
      <secondary>encrypting</secondary>
    </indexterm>

    <para>Swap encryption in &os; is easy to configure and has been
      available since &os; 5.3-RELEASE.  Depending on which version
      of &os; is being used, different options are available
      and configuration can vary slightly.  From &os; 6.0-RELEASE onwards,
      the &man.gbde.8; or &man.geli.8; encryption systems can be used
      for swap encryption.  With earlier versions, only &man.gbde.8; is
      available.  Both systems use the <filename>encswap</filename>
      <link linkend="configtuning-rcd">rc.d</link> script.</para>

    <para>The previous section, <link linkend="disks-encrypting">Encrypting
      Disk Partitions</link>, includes a short discussion on the different
      encryption systems.</para>

    <sect2>
      <title>Why should Swap be Encrypted?</title>

      <para>Like the encryption of disk partitions, encryption of swap space
	is done to protect sensitive information.  Imagine an application
	that e.g. deals with passwords.  As long as these passwords stay in
	physical memory, all is well.  However, if the operating system starts
	swapping out memory pages to free space for other applications, the
	passwords may be written to the disk platters unencrypted and easy to
	retrieve for an adversary.  Encrypting swap space can be a solution for
	this scenario.</para>
    </sect2>

    <sect2>
      <title>Preparation</title>

      <note>
	<para>For the remainder of this section, <filename>ad0s1b</filename>
	  will be the swap partition.</para>
      </note>

      <para>Up to this point the swap has been unencrypted.  It is possible that
	there are already passwords or other sensitive data on the disk platters
	in cleartext.  To rectify this, the data on the swap partition should be
	overwritten with random garbage:</para>

      <screen>&prompt.root; <userinput>dd if=/dev/random of=/dev/ad0s1b bs=1m</userinput></screen>
    </sect2>

    <sect2>
      <title>Swap Encryption with &man.gbde.8;</title>

      <para>If &os; 6.0-RELEASE or newer is being used, the
	<literal>.bde</literal> suffix should be added to the device in the
	respective <filename>/etc/fstab</filename> swap line:</para>

      <screen>
# Device                Mountpoint      FStype  Options         Dump    Pass#
/dev/ad0s1b.bde         none            swap    sw              0       0
      </screen>

      <para>For systems prior to &os; 6.0-RELEASE, the following line
	in <filename>/etc/rc.conf</filename> is also needed:</para>

      <programlisting>gbde_swap_enable="YES"</programlisting>
    </sect2>

    <sect2>
      <title>Swap Encryption with &man.geli.8;</title>

      <para>Alternatively, the procedure for using &man.geli.8; for swap
	encryption is similar to that of using &man.gbde.8;.  The
	<literal>.eli</literal> suffix should be added to the device in the
	respective <filename>/etc/fstab</filename> swap line:</para>

      <screen>
# Device                Mountpoint      FStype  Options         Dump    Pass#
/dev/ad0s1b.eli         none            swap    sw              0       0
      </screen>

      <para>&man.geli.8; uses the <acronym>AES</acronym> algorithm with
	a key length of 256 bit by default.</para>

      <para>Optionally, these defaults can be altered using the
	<literal>geli_swap_flags</literal> option in
	<filename>/etc/rc.conf</filename>.  The following line tells the
	<filename>encswap</filename> rc.d script to create &man.geli.8; swap
	partitions using the Blowfish algorithm with a key length of 128 bit,
	a sectorsize of 4 kilobytes and the <quote>detach on last close</quote>
	option set:</para>

      <programlisting>geli_swap_flags="-a blowfish -l 128 -s 4096 -d"</programlisting>

      <para>Please refer to the description of the <command>onetime</command> command
	in the &man.geli.8; manual page for a list of possible options.</para>
    </sect2>

    <sect2>
      <title>Verifying that it Works</title>

      <para>Once the system has been rebooted, proper operation of the
	encrypted swap can be verified using the
	<command>swapinfo</command> command.</para>

      <para>If &man.gbde.8; is being used:</para>

      <screen>&prompt.user; <userinput>swapinfo</userinput>
Device          1K-blocks     Used    Avail Capacity
/dev/ad0s1b.bde    542720        0   542720     0%
      </screen>

      <para>If &man.geli.8; is being used:</para>

      <screen>&prompt.user; <userinput>swapinfo</userinput>
Device          1K-blocks     Used    Avail Capacity
/dev/ad0s1b.eli    542720        0   542720     0%
      </screen>
    </sect2>
  </sect1>
</chapter>