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.\"     From: @(#)savecore.8	8.1 (Berkeley) 6/5/93
.\" $FreeBSD: src/sbin/savecore/savecore.8,v 1.8.2.6 2002/06/20 23:09:09 charnier Exp $
.\" $DragonFly: src/sbin/savecore/savecore.8,v 1.7 2006/10/20 18:30:12 corecode Exp $
.\"
.Dd October 20, 2006
.Dt SAVECORE 8
.Os
.Sh NAME
.Nm savecore
.Nd "save a core dump of the operating system"
.Sh SYNOPSIS
.Nm
.Fl c
.Nm
.Op Fl fkvz
.Op Fl N Ar system
.Op Fl P Ar physmem
.Op Fl B Ar blkno
.Op Fl D Ar device
.Ar directory
.Sh DESCRIPTION
The
.Nm
utility
copies the currently running kernel and its associated core dump into
.Fa directory ,
and enters a reboot message and information about the core dump into
the system log.
.Pp
The options are as follows:
.Bl -tag -width indent
.It Fl c
Clear the dump, so that future invocations of
.Nm
will ignore it.
.It Fl f
Force a dump to be taken even if the dump doesn't appear correct or there
is insufficient disk space.
.It Fl k
Do not clear the dump after saving it.
.It Fl N
Use
.Ar system
as the kernel instead of the running kernel (as determined from
.Xr getbootfile 3 ) .
.It Fl P
Specify physical memory size used at dumptime (cf. the
.Va hw.physmem
kernel environment variable).
.It Fl B
Specify offset of dump in blocks (as printed at dumptime).
.It Fl D
Specify an alternative device to obtain the dump from.
Unless your current
.Va dumpdev
and
.Ar device
have the same size, you will need to specify
the block offset of the dump with
.Fl B .
.It Fl v
Print out some additional debugging information.
.It Fl z
Compress the core dump and kernel (see
.Xr gzip 1 ) .
.El
.Pp
The
.Nm
utility
checks the core dump in various ways to make sure that it is current and
that it corresponds to the currently running system.
If it passes these checks, it saves the core image in
.Ar directory Ns Pa /vmcore.#
and the system in
.Ar directory Ns Pa /kernel.#
The ``#'' is the number from the first line of the file
.Ar directory Ns Pa /bounds ,
and it is incremented and stored back into the file each time
.Nm
successfully runs.
.Pp
The
.Nm
utility
also checks the available disk space before attempting to make the copies.
If there is insufficient disk space in the filesystem containing
.Ar directory ,
or if the file
.Ar directory Ns Pa /minfree
exists and the number of free kilobytes (for non-superusers) in the
filesystem after the copies were made would be less than the number
in the first line of this file, the copies are not attempted.
.Pp
If
.Nm
successfully copies the kernel and the core dump, the core dump is cleared
so that future invocations of
.Nm
will ignore it.
.Pp
The
.Nm
utility
is meant to be called near the end of the initialization file
.Pa /etc/rc
(see
.Xr rc 8 ) .
.Sh SEE ALSO
.Xr gzip 1 ,
.Xr getbootfile 3 ,
.Xr dumpon 8 ,
.Xr loader 8 ,
.Xr syslogd 8
.Sh HISTORY
The
.Nm
utility appeared in
.Bx 4.1 .
.Sh BUGS
The minfree code does not consider the effect of compression.