From eaddbc626798374a41e5746660143d76e778bc2c Mon Sep 17 00:00:00 2001 From: jkoshy Date: Wed, 27 May 1998 11:05:59 +0000 Subject: Correct manual page, based on feedback from Bruce Evans. Reviewed by: Bruce Evans --- sbin/dumpon/dumpon.8 | 64 +++++++++++++++++++++++++++------------------------- 1 file changed, 33 insertions(+), 31 deletions(-) (limited to 'sbin/dumpon') diff --git a/sbin/dumpon/dumpon.8 b/sbin/dumpon/dumpon.8 index 296e92e..5d7aea6 100644 --- a/sbin/dumpon/dumpon.8 +++ b/sbin/dumpon/dumpon.8 @@ -30,7 +30,7 @@ .\" SUCH DAMAGE. .\" .\" From: @(#)swapon.8 8.1 (Berkeley) 6/5/93 -.\" $Id: dumpon.8,v 1.5 1997/02/22 14:32:21 peter Exp $ +.\" $Id: dumpon.8,v 1.6 1998/05/25 08:54:40 jkoshy Exp $ .\" .Dd May 12, 1995 .Dt DUMPON 8 @@ -41,45 +41,45 @@ .Sh SYNOPSIS .Nm dumpon .Op Fl v -.Ar swap_device +.Ar special_file +.Nm dumpon +.Op Fl v +.Ar off .Sh DESCRIPTION .Nm Dumpon is used to specify a device where the kernel can save a crash dump in the case of a panic. .Pp -The system begins with no dump area configured for safety. If a -.Dq dumps on -clause is specified in the kernel configuration file -or if the variable -.Dq Li dumpdev -in the boot time configuration file -.Pa /etc/rc.conf -names a dump device, future panics will cause the kernel -to save a crash dump on the specified dump device. -The dump device must be one of the swap areas -specified in the filesystem configuration file -.Pa /etc/fstab , -and it must be at least the size of physical memory. -.Pp -Calls to -.Nm dumpon -normally occur in the system multi-user initialization file +Calls to +.Nm +normally occur from the system multi-user initialization file .Pa /etc/rc , -before the -.Xr savecore 8 -program is run. +controlled by the +.Dq dumpdev +variable in the boot time configuration file +.Pa /etc/rc.conf . +.Pp +The size of the specified dump device must be at least 64 KB greater the +size of physical memory. +.Pp The .Fl v -flag can be specified to cause the +flag causes .Nm -program to be verbose about its activity. +to be verbose about its activity. .Sh NOTES +One of the system swap devices is usually chosen as the dump device, as +swap devices are the most likely to have the required space at dump time. .Pp -Hardcoding the dump device using the kernel configuration file -is only useful if a kernel crashes before reaching multi-user mode. -Otherwise, the use of +The dump device can also be specified at kernel compile time using +the +.Dq dumps on +clause in the kernel configuration file (see +.Xr config 8 ). +This is useful when the kernel panics before multi-user mode +is reached. Subsequent successful invocations of .Nm -to specify the dump device is recommended. +will override the compiled in value. .Pp The .Nm @@ -93,7 +93,7 @@ or to .Dv NODEV (meaning that no dumps are to be taken) if .Ar special_file -is the text string +is the text string: .Dq Li off . .Sh SEE ALSO .Xr sysctl 3 , @@ -109,14 +109,16 @@ is the text string .Bl -tag -width /dev/[ws]d?b -compact .It Pa /dev/[ws]d?b standard swap areas -.It Pa /etc/fstab -static filesystem and swap information .It Pa /etc/rc.conf boot-time system configuration .El .Sh BUGS Because the filesystem layer is already dead by the time a crash dump is taken, it is not possible to send crash dumps directly to a file. +.Pp +.Nm +currently allows only devices with minor number 1 to be used as dump +devices. .Sh HISTORY The .Nm -- cgit v1.1