System information

XFS file system backup and restoration involves two utilities: xfsd ump and xfsresto re.
To backup or dump an XFS file system, use the xfsd ump utility. Red Hat Enterprise Linux 6 supports
backups to tape drives or regular file images, and also allows multiple dumps to be written to the
same tape. The xfsd ump utility also allows a dump to span multiple tapes, although only one dump
can be written to a regular file. In addition, xfsd ump supports incremental backups, and can exclude
files from a backup using size, subtree, or inode flags to filter them.
In order to support incremental backups, xfsd ump uses dump levels to determine a base dump to
which a specific dump is relative. The -l option specifies a dump level (0-9). To perform a full
backup, perform a level 0 dump on the file system (that is, /path/to/filesystem), as in:
# xfsd ump -l 0 -f /d ev/device /path/to/filesystem
Note
The -f option specifies a destination for a backup. For example, the /d ev/st0 destination is
normally used for tape drives. An xfsd ump destination can be a tape drive, regular file, or
remote tape device.
In contrast, an incremental backup will only dump files that changed since the last level 0 dump. A
level 1 dump is the first incremental dump after a full dump; the next incremental dump would be level
2, and so on, to a maximum of level 9. So, to perform a level 1 dump to a tape drive:
# xfsd ump -l 1 -f /d ev/st0 /path/to/filesystem
Conversely, the xfsresto re utility restores file systems from dumps produced by xfsd ump. The
xfsresto re utility has two modes: a default simple mode, and a cumulative mode. Specific dumps are
identified by session ID or session label. As such, restoring a dump requires its corresponding session
ID or label. To display the session ID and labels of all dumps (both full and incremental), use the -I
option:
# xfsresto re -I
This will provide output similar to the following:
Examp le 8.4 . Sessio n ID an d lab els o f all d ump s
file system 0:
fs id: 45e9af35-efd2-4244-87bc-4762e476cbab
session 0:
mount point: bear-05:/mnt/test
device: bear-05:/dev/sdb2
time: Fri Feb 26 16:55:21 2010
session label: "my_dump_session_label"
session id: b74a3586-e52e-4a4a-8775-c3334fa8ea2c
level: 0
resumed: NO
subtree: NO
streams: 1
stream 0:
pathname: /mnt/test2/backup
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