.\" 2. Redistributions in binary form must reproduce the above copyright
.\" notice, this list of conditions and the following disclaimer in the
.\" documentation and/or other materials provided with the distribution.
-.\" 3. All advertising materials mentioning features or use of this software
-.\" must display the following acknowledgement:
-.\" This product includes software developed by the University of
-.\" California, Berkeley and its contributors.
-.\" 4. Neither the name of the University nor the names of its contributors
+.\" 3. Neither the name of the University nor the names of its contributors
.\" may be used to endorse or promote products derived from this software
.\" without specific prior written permission.
.\"
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
-.\" $Id: dump.8.in,v 1.50 2003/03/06 14:35:51 stelian Exp $
+.\" $Id: dump.8.in,v 1.62 2009/06/18 09:40:03 stelian Exp $
.\"
.TH DUMP 8 "version __VERSION__ of __DATE__" BSD "System management commands"
.SH NAME
dump \- ext2/3 filesystem backup
.SH SYNOPSIS
.B dump
-[\fB\-0123456789ackMnqSuv\fR]
+[\fB\-\fIlevel#\fR]
+[\fB\-ackMnqSuv]
[\fB\-A \fIfile\fR]
[\fB\-B \fIrecords\fR]
[\fB\-b \fIblocksize\fR]
[\fB\-Q \fIfile\fR]
[\fB\-s \fIfeet\fR]
[\fB\-T \fIdate\fR]
+[\fB\-y\fR]
[\fB\-z\fIcompression level\fR]
.I files-to-dump
.PP
.B dump
[\fB\-W \fR| \fB\-w\fR]
-.PP
-(The 4.3BSD option syntax is implemented for backward compatibility but is not
-documented here.)
.SH DESCRIPTION
.B Dump
examines files on an ext2/3 filesystem and determines which files need to be
The following options are supported by
.B dump:
.TP
-.BI \-0\-9
-Dump levels. A level 0, full backup, guarantees the entire file system is
-copied (but see also the
+.BI \-level#
+The dump level (any integer). A level 0, full backup, specified by
+.B \-0
+guarantees the entire file system is copied (but see also the
.B \-h
option below). A level number above 0, incremental backup, tells
.B dump
to
copy all files new or modified since the last dump of a lower level. The
-default level is 9.
+default level is 0. Historically only levels 0 to 9 were usable in
+dump, this version is able to understand any integer as a dump level.
.TP
.BI \-a
\*(lqauto-size\*(rq. Bypass all tape length calculations, and write until an
to determine whether a file is in the dump file that is being restored.
.TP
.BI \-b " blocksize"
-The number of kilobytes per dump record. The default blocksize is 10
-and the maximal value is 1024.
+The number of kilobytes per dump record. The default blocksize is 10,
+unless the
+.B \-d
+option has been used to specify a tape density of 6250BPI or more,
+in which case the default blocksize is 32. Th maximal value is 1024.
Note however that, since the IO system slices all requests into chunks
of
.B MAXBSIZE
.B dump
waits for you to change the volume. This option overrides the calculation of
tape size based on length and density. If compression is on this limits the
-size of the compressed output per volume.
+size of the compressed output per volume. Multiple values may be given
+as a single argument separated by commas. Each value will be used for one
+dump volume in the order listed; if
+.B dump
+creates more volumes than the
+number of values given, the last value will be used for the remaining
+volumes. This is useful for filling up already partially filled media
+(and then continuing with full size volumes on empty media) or mixing media
+of different sizes.
.TP
.BI \-c
Change the defaults for use with a cartridge tape drive, with a density of 8000
or
.I user@host:file
.B dump
-writes to the named file on the remote host using
+writes to the named file on the remote host (which should already
+exist, dump doesn't create a new remote file) using
.BR rmt (8).
The default path name of the remote
.BR rmt (8)
are saved in a regular way. Uses of this flag must be consistent, meaning that
either every dump in an incremental dump set have the flag, or no one has it.
.IP
+If you use this option, be aware that many programs that unpack
+files from archives (e.g. tar, rpm, unzip, dpkg) may set files'
+mtimes to dates in the past. Files installed in this way may not be
+dumped correctly using "dump -m" if the modified mtime is earlier
+than the previous level dump.
+.IP
Tapes written using such 'metadata only' inodes will not be compatible with the
BSD tape format or older versions of
.B restore.
.B dump
to print out, for all file systems in
.I __DUMPDATES__ ,
-and regognized file systems in
+and recognized file systems in
.I /etc/mtab
and
.IR /etc/fstab .
.I /etc/fstab
which need to be dumped.
.TP
+.BI \-y
+Compress every block to be written to the tape using the lzo library.
+This doesn't compress as well as the zlib library but it's much faster.
+This option will work only when dumping to a file or pipe or, when dumping to
+a tape drive, if the tape drive is capable of writing variable length blocks.
+You will need at least the 0.4b34 version of
+.B restore
+in order to extract compressed tapes. Tapes written using compression will not
+be compatible with the BSD tape format.
+.TP
.BI \-z "compression level"
Compress every block to be written on the tape using zlib library. This option
will work only when dumping to a file or pipe or, when dumping to a tape drive,
This should be done at set intervals, say once a month or once every two months,
and on a set of fresh tapes that is saved forever.
.IP \(em
-After a level 0, dumps of active file systems are taken on a daily basis, using
-a modified Tower of Hanoi algorithm, with this sequence of dump levels:
+After a level 0, dumps of active file systems are taken on a daily basis,
+with this sequence of dump levels:
.RS 14
.B 3 2 5 4 7 6 9 8 9 9 ...
.RE
.PP
After several months or so, the daily and weekly tapes should get rotated out
of the dump cycle and fresh tapes brought in.
+.PP
+Another backup strategy is the Tower of Hanoi sequence, which reuses
+older tapes in a way that for newer dates the available restore points
+are more frequent, then for older dates (see
+http://en.wikipedia.org/wiki/Backup_rotation_scheme for additional
+information).
+.PP
+(The 4.3BSD option syntax is implemented for backward compatibility but is not
+documented here.)
.SH ENVIRONMENT
.TP
.B TAPE
.B dump
provided that the machine on which
.B dump
-is run did not change timezones (which should be a fairly rare occurence).
+is run did not change timezones (which should be a fairly rare occurrence).
.SH EXIT STATUS
.B Dump
exits with zero status on success. Startup errors are indicated with an exit
When a read error occurs,
.B dump
prints out the corresponding physical disk block and sector number and the
-ext2/3 logical block number. It doesn't print out the corresponing file name or
+ext2/3 logical block number. It doesn't print out the corresponding file name or
even the inode number. The user has to use
.BR debugfs (8),
commands
backup suite was ported to Linux's Second Extended File System by Remy Card
<card@Linux.EU.Org>. He maintained the initial versions of
.B dump
-(up and including 0.4b4, released in january 1997).
+(up and including 0.4b4, released in January 1997).
.PP
Starting with 0.4b5, the new maintainer is Stelian Pop <stelian@popies.net>.
.SH AVAILABILITY
git.wh0rd.org / dump.git / blobdiff