Differential D11723 Diff 34309 head/sbin/dumpon/dumpon.8

Changeset View

Standalone View

head/sbin/dumpon/dumpon.8

	Show All 22 Lines
	.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT			.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY			.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF			.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	.\" SUCH DAMAGE.			.\" SUCH DAMAGE.
	.\"			.\"
	.\" From: @(#)swapon.8 8.1 (Berkeley) 6/5/93			.\" From: @(#)swapon.8 8.1 (Berkeley) 6/5/93
	.\" $FreeBSD$			.\" $FreeBSD$
	.\"			.\"
	.Dd December 10, 2016			.Dd October 24, 2017
	.Dt DUMPON 8			.Dt DUMPON 8
	.Os			.Os
	.Sh NAME			.Sh NAME
	.Nm dumpon			.Nm dumpon
	.Nd "specify a device for crash dumps"			.Nd "specify a device for crash dumps"
	.Sh SYNOPSIS			.Sh SYNOPSIS
	.Nm			.Nm
	.Op Fl v			.Op Fl v
	.Op Fl k Ar public_key_file			.Op Fl k Ar public_key_file
				.Op Fl z
	.Ar special_file			.Ar special_file
	.Nm			.Nm
	.Op Fl v			.Op Fl v
	.Cm off			.Cm off
	.Nm			.Nm
	.Op Fl v			.Op Fl v
	.Fl l			.Fl l
	.Sh DESCRIPTION			.Sh DESCRIPTION
	▲ Show 20 Lines • Show All 60 Lines • ▼ Show 20 Lines
	.Pa /etc/rc.d/dumpon			.Pa /etc/rc.d/dumpon
	.Xr rc 8			.Xr rc 8
	script.			script.
	This flag requires a kernel compiled with the			This flag requires a kernel compiled with the
	.Dv EKCD			.Dv EKCD
	kernel option.			kernel option.
	.Pp			.Pp
	The			The
				.Fl z
				option configures the kernel to compress the dump in gzip format before writing
				it to the dump device.
				This reduces the amount of space required for the dump and accelerates
				recovery with
				.Xr savecore 8
				since less data needs to be copied from the dump device.
				When compression is enabled, the
				.Nm
				utility will not verify that the dump device is sufficiently large for a full
				dump.
				This flag requires a kernel compiled with the
				.Dv GZIO
				kernel option.
				.Pp
				The
	.Fl l			.Fl l
	flag causes			flag causes
	.Nm			.Nm
	to print the current dump device or _PATH_DEVNULL ("/dev/null") if no device is			to print the current dump device or _PATH_DEVNULL ("/dev/null") if no device is
	configured.			configured.
	.Pp			.Pp
	The			The
	.Fl v			.Fl v
	▲ Show 20 Lines • Show All 142 Lines • ▼ Show 20 Lines
	.Sh HISTORY			.Sh HISTORY
	The			The
	.Nm			.Nm
	utility appeared in			utility appeared in
	.Fx 2.0.5 .			.Fx 2.0.5 .
	.Sh BUGS			.Sh BUGS
	Because the file system layer is already dead by the time a crash dump			Because the file system layer is already dead by the time a crash dump
	is taken, it is not possible to send crash dumps directly to a file.			is taken, it is not possible to send crash dumps directly to a file.
				.Pp
				It is currently not possible to configure both compression and encryption.
				The encrypted dump format assumes that the kernel dump size is a multiple
				of the cipher block size, which may not be true when the dump is compressed.