savecore

SAVECORE(8)                 System Manager's Manual                SAVECORE(8)

NAME
     savecore — save a core dump of the operating system

SYNOPSIS
     savecore -c [-v] [device ...]
     savecore -C [-v] [device ...]
     savecore [--libxo] [-fkvz] [-m maxdumps] [directory [device ...]]

DESCRIPTION
     The savecore utility copies a core dump into directory, or the current
     working directory if no directory argument is given, and enters a reboot
     message and information about the core dump into the system log.

     The options are as follows:

     --libxo      Generate output via libxo(3) in a selection of different
                  human and machine readable formats.  See xo_parse_args(3)
                  for details on command line arguments.

     -C           Check to see if a dump exists, and display a brief message
                  to indicate the status.  An exit status of 0 indicates that
                  a dump is there, 1 indicates that none exists.  This option
                  is compatible only with the [-v] option.

     -c           Clear the dump, so that future invocations of savecore will
                  ignore it.

     -f           Force a dump to be taken even if either the dump was cleared
                  or if the dump header information is inconsistent.

     -k           Do not clear the dump after saving it.

     -m maxdumps  Maximum number of dumps to store.  Once the number of stored
                  dumps is equal to maxdumps the counter will restart from 0.

     -v           Print out some additional debugging information.  Specify
                  twice for more information.

     -z           Compress the dump (see gzip(1)).  The dump may already be
                  compressed if the kernel was configured to do so by
                  dumpon(8).  In this case, the option has no effect.

     The savecore utility looks for dumps on each device specified by the
     device argument(s), or on each device in /etc/fstab marked as “dump” or
     “swap”.  The savecore utility checks the core dump in various ways to
     make sure that it is complete.  If it passes these checks, it saves the
     core image in directory/vmcore.# and information about the core in
     directory/info.#.  If the core is encrypted, it saves the dump key in
     directory/key.#.  The core can be later decrypted using decryptcore(8).
     For kernel textdumps generated with the textdump(4) facility, output will
     be stored in the tar(5) format and named directory/textdump.tar.#.  The
     “#” is the number from the first line of the file directory/bounds, and
     it is incremented and stored back into the file each time savecore
     successfully runs.

     The savecore utility also checks the available disk space before
     attempting to make the copies.  If there is insufficient disk space in
     the file system containing directory, or if the file directory/minfree
     exists and the number of free kilobytes (for non-superusers) in the file
     system after the copies were made would be less than the number in the
     first line of this file, the copies are not attempted.

     If savecore successfully copies the kernel and the core dump, the core
     dump is cleared so that future invocations of savecore will ignore it.

     The savecore utility is meant to be called near the end of the
     initialization file /etc/rc (see rc(8)).

SEE ALSO
     gzip(1), getbootfile(3), libxo(3), xo_parse_args(3), textdump(4), tar(5),
     crashinfo(8), decryptcore(8), dumpon(8), syslogd(8)

HISTORY
     The savecore utility appeared in 4.1BSD.

     Support for kernel textdumps appeared in FreeBSD 7.1.

BUGS
     The minfree code does not consider the effect of compression or sparse
     files.

                                March 17, 2018