diff options
Diffstat (limited to 'sbin/tunefs/tunefs.8')
| -rw-r--r-- | sbin/tunefs/tunefs.8 | 42 |
1 files changed, 38 insertions, 4 deletions
diff --git a/sbin/tunefs/tunefs.8 b/sbin/tunefs/tunefs.8 index 065844a831cd..97de1abf33c0 100644 --- a/sbin/tunefs/tunefs.8 +++ b/sbin/tunefs/tunefs.8 @@ -25,10 +25,7 @@ .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF .\" SUCH DAMAGE. .\" -.\" @(#)tunefs.8 8.2 (Berkeley) 12/11/93 -.\" $FreeBSD$ -.\" -.Dd January 29, 2019 +.Dd November 17, 2023 .Dt TUNEFS 8 .Os .Sh NAME @@ -95,6 +92,41 @@ this parameter should be set higher. Specify the expected average file size. .It Fl j Cm enable | disable Turn on/off soft updates journaling. +.Pp +Enabling journaling reduces the time spent by +.Xr fsck_ffs 8 +cleaning up a filesystem after a crash to a few seconds from minutes to hours. +Without journaling, the time to recover after a crash is a function +of the number of files in the filesystem and the size of the filesystem. +With journaling, the time to recover after a crash is a function of the +amount of activity in the filesystem in the minute before the crash. +Journaled recovery time is usually only a few seconds and never +exceeds a minute. +.Pp +The drawback to using journaling is that the writes to its log adds +an extra write load to the media containing the filesystem. +Thus a write-intensive workload will have reduced throughput on a +filesystem running with journaling. +.Pp +Like all journaling filesystems, the journal recovery will only fix +issues known to the journal. +Specifically if a media error occurs, +the journal will not know about it and hence will not fix it. +Thus when using journaling, it is still necessary to run a full fsck +every few months or after a filesystem panic to check for and fix +any errors brought on by media failure. +A full fsck can be done by running a background fsck on a live +filesystem or by running with the +.Fl f +flag on an unmounted filesystem. +When running +.Xr fsck_ffs 8 +in background on a live filesystem the filesystem performance +will be about half of normal during the time that the background +.Xr fsck_ffs 8 +is running. +Running a full fsck on a UFS filesystem is the equivalent of +running a scrub on a ZFS filesystem. .It Fl J Cm enable | disable Turn on/off gjournal flag. .It Fl k Ar held-for-metadata-blocks @@ -184,6 +216,8 @@ specified mount point. .El .Sh SEE ALSO .Xr fs 5 , +.Xr ffs 7 , +.Xr tuning 7 , .Xr dumpfs 8 , .Xr gjournal 8 , .Xr growfs 8 , |