dump rdump
filesystem backup
dump [-0123456789cnu] [-B records] [-b blocksize] [-d density] [-f file] [-h level] [-s feet] [-T date] filesystem
dump -W | -w
Backs up files to disk, tape or other medium (see -f
remote destination).
By default, the same output file name is used for each volume
-0..9 Dump levels.
A level 0, full backup saves the entire file system
For an incremental backup, dump saves files which are new or modified since the last dump of the same or lower level.
The default level is 9.
| -T date
Use the date as the starting time for the dump instead of the time determined from
looking in /etc/dumpdates . The format of date is the same as that of ctime(3).
Useful for automated dump scripts to dump over a specific period of time.
-T option is mutually exclusive from -u .
| -u Update /etc/dumpdates after a successful dump. The format of /etc/dumpdates
is readable by people, consisting of one free format record per line: filesystem name, increment level
and ctime(3) format dump date.
There may be only one entry per filesystem at each level. /etc/dumpdates may be edited to change any of the fields,
| -W outputs the file systems to be dumped based on /etc/dumpdates and /etc/fstab ,
the most recent dump date and level, and highlights those file systems
that should be dumped.
If -W is set, other options are ignored
| -w Is like W, but outputs only those filesystems which need to be dumped.
| -f file
Write the backup to file which may be a special device file like /dev/rmt12 (a tape drive),
/dev/rdisk1s3 (a disk drive), an ordinary file, or `-' (the standard output).
Multiple file names may be given as a single argument separated by commas.
Each file will be used for one volume in the order listed; if the dump requires more volumes than the number of names
given, the last file name will used for all remaining volumes after prompting for media
changes.
If the name of the file is of the form ``host:file'', or ``user@host:file'', dump
writes to the named file on the remote host using rmt(8).
| -h level Honor nodump , i.e. ignore files that should not (usually) be dumpped as indicated by the NO_DUMP attribute.
for dumps at or above the given level.
The default honor level is 1, so that incremental backups omit such files but full backups retain them.
| -b blocksize kilobytes per dump record.
|
A dump that is larger than the output medium is broken into multiple
volumes. On tape the size is determined by writing until an end-of-media indication is returned.
On media that cannot reliably return an end-of-media indication (such as some cartridge tape drives)
each volume is of a fixed size determined by the tape length and density and/or block count options .
| -B blocks Next volume is started after number of blocks . overrides -c
| -s feet when feet tape is written, dump prompts for a new tape.
The default tape length is 2300 feet.
| -c calculate tape size for cartridge tapes.
-d density Set tape density . The default is 1600BPI.
| -n When dump requires operator attention, notify all operators in the group ``operator'' by
means similar to a wall(1).
Dump requires operator intervention on: end of tape, end of dump, tape write error,
tape open error or disk read error (if there are more than a threshold of 32). In addition to alerting
all operators implied by the -n key, dump interacts with the operator on dump's control terminal at
times when dump can no longer proceed, or if something is grossly wrong. All questions dump poses must
be answered by typing ``yes'' or ``no''
| | | | | | | | | | | | | | |
dump checkpoints at the start of each volume. If writing that volume fails, dump will, restart from the checkpoint
Dump notifies the operator at periodic intervals, including usually low estimates of the
number of blocks to write, the number of tapes it will take, the time to completion, and the time to
the tape change. The output is verbose,
In the event of a catastrophic disk event, the time required to restore all the necessary backup tapes
or files to disk can be kept to a minimum by staggering the incremental dumps. An efficient method of
staggering incremental dumps to minimize the number of tapes follows:
o start with a level 0 backup, for example:
/sbin/dump -0u -f /dev/nrst1 /usr/src
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.
o After a level 0, dumps of active file systems are taken on a daily basis, using an
algorithm, with this sequence of dump levels:
3 2 5 4 7 6 9 8 9 9 ...
For the daily dumps, it should be possible to use a fixed number of tapes for each day, used
on a weekly basis. Each week, a level 1 dump is taken, and the daily Hanoi sequence repeats
beginning with 3. For weekly dumps, another fixed set of tapes per dumped file system is
used, also on a cyclical basis.
After several months or so, the daily and weekly tapes should get rotated out of the dump cycle and
fresh tapes brought in.
FILES
/dev/rmt8 default tape unit to dump to
/etc/dumpdates dump date records
/etc/fstab dump table: file systems and frequency
/etc/group to find group operator
SEE restore(8), rmt(8), dump(5), fstab(5)
mkfs.f2fs(8), fsck.f2fs(8), defrag.f2fs(8), resize.f2fs(8), sload.f2fs(8).
DIAGNOSTICS
Dump exits with zero status on success.
Startup errors are indicated with an exit code of 1;
abnormal termination is indicated with an exit code of 3.
BUGS
Fewer than 32 read errors on the filesystem do not cause dump to abort.
Each reel requires a new process, so parent processes for reels already written wait until
the entire tape is written.
Dump with -W or -w does not report filesystems that have never been recorded in /etc/dumpdates
.
Enhancments include: underanding of the dump sequence, kept track of the vollumes writ on, notified the
operator which volume to use and provided more assistance for the operator running restore.
HISTORY
A dump command appeared in Version 6 AT&T UNIX.
May 1, 1995 4th Berkeley Distribution
dump.f2fs
retrieve directory and file entries from an F2FS-formated image
dump.f2fs [ -i inode number ] [ -s SIT range ] [ -a SSA range ] [ -b block address ] [ -d debugging-level ] device
Retrieve f2fs metadata (usually in a disk partition). device is the special file corresponding to the device (e.g. /dev/sdXX).
it can retrieve
- a file given its inode number,
- SIT entries into a file,
- SSA entries into a file,
- reverse information from the given block address.
-i inode number inode number to dump out.
| -s SIT range range presented by segment numbers to dump SIT entries.
| -a SSA range range presented by segment numbers to dump SSA entries.
| -b block address block address to retrieve its metadata information.
| -d debug-level level of debugging options. The default number is 0, which shows basic debugging messages.
| | | | | |
The exit code returned by dump.f2fs is 0 on success and -1 on failure.
AVAILABILITY
dump.f2fs is available from git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs-tools.git.