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-rw-r--r--sbin/dumpon/dumpon.815
1 files changed, 11 insertions, 4 deletions
diff --git a/sbin/dumpon/dumpon.8 b/sbin/dumpon/dumpon.8
index 2c09e85cda85..6be80909415b 100644
--- a/sbin/dumpon/dumpon.8
+++ b/sbin/dumpon/dumpon.8
@@ -28,7 +28,7 @@
.\" From: @(#)swapon.8 8.1 (Berkeley) 6/5/93
.\" $FreeBSD$
.\"
-.Dd May 12, 1995
+.Dd April 29, 2013
.Dt DUMPON 8
.Os
.Sh NAME
@@ -59,14 +59,21 @@ controlled by the
variable in the boot time configuration file
.Pa /etc/rc.conf .
.Pp
-For most systems the size of the specified dump device must be at
+The default type of kernel crash dump is the mini crash dump.
+Mini crash dumps hold only memory pages in use by the kernel.
+Alternatively, full memory dumps can be enabled by setting the
+.Va debug.minidump
+.Xr sysctl 8
+variable to 0.
+.Pp
+For systems using full memory dumps, the size of the specified dump
+device must be at
least the size of physical memory.
Even though an additional 64 kB header is added to the dump, the BIOS for a
platform typically holds back some memory, so it is not usually
necessary to size the dump device larger than the actual amount of RAM
available in the machine.
-.Pp
-The
+Also, when using full memory dumps, the
.Nm
utility will refuse to enable a dump device which is smaller than the
total amount of physical memory as reported by the