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33 .\" $Id: dump.8.in,v 1.16 2000/08/19 23:48:10 stelian Exp $
37 .Os "dump __VERSION__"
40 .Nd ext2 filesystem backup
43 .Op Fl 0123456789ackMnSu
47 .Op Fl e Ar inode number
61 option syntax is implemented for backward compatibility but
62 is not documented here.)
67 and determines which files
68 need to be backed up. These files
69 are copied to the given disk, tape or other
70 storage medium for safe keeping (see the
72 option below for doing remote backups).
73 A dump that is larger than the output medium is broken into
75 On most media the size is determined by writing until an
76 end-of-media indication is returned. This can be enforced
81 On media that cannot reliably return an end-of-media indication
82 (such as some cartridge tape drives),
83 each volume is of a fixed size;
84 the actual size is determined by the tape size, density and/or
85 block count options below.
86 By default, the same output file name is used for each volume
87 after prompting the operator to change media.
90 is either a mountpoint of a filesystem
91 or a directory to be backed up as a subset of a filesystem.
92 In the former case, either the path to a mounted filesystem
93 or the device of an unmounted filesystem can be used.
94 In the latter case, certain restrictions are placed on the backup:
96 is not allowed and the only dump level that is supported is
99 The following options are supported by
104 A level 0, full backup,
105 guarantees the entire file system is copied
109 A level number above 0,
114 copy all files new or modified since the
115 last dump of a lower level.
116 The default level is 9.
118 The number of 1 KB blocks per volume.
119 This option overrides the calculation of tape size
120 based on length and density.
123 Bypass all tape length considerations, and enforce writing
124 until an end-of-media indication is returned. This fits best
125 for most modern tape drives. Use of this option is particularly
126 recommended when appending to an existing tape, or using a tape
127 drive with hardware compression (where you can never be sure about
128 the compression ratio).
129 .It Fl b Ar blocksize
130 The number of kilobytes per dump record.
131 Since the IO system slices all requests into chunks of MAXBSIZE
132 (typically 64KB), it is not possible to use a larger blocksize
133 without having problems later with
137 will constrain writes to MAXBSIZE.
138 The default blocksize is 10.
140 Change the defaults for use with a cartridge tape drive, with a density
141 of 8000 bpi, and a length of 1700 feet.
145 from the dump (you can use
147 to find the inode number for a file or directory).
153 only for dumps at or above the given
155 The default honor level is 1,
156 so that incremental backups omit such files
157 but full backups retain them.
161 The default is 1600BPI.
166 may be a special device file
171 (a floppy disk drive),
175 (the standard output).
176 Multiple file names may be given as a single argument separated by commas.
177 Each file will be used for one dump volume in the order listed;
178 if the dump requires more volumes than the number of names given,
179 the last file name will used for all remaining volumes after prompting
181 If the name of the file is of the form
186 writes to the named file on the remote host using
188 The default path name of the remote
191 .\" rmt path, is the path on the remote host
193 this can be overridden by the environment variable
196 Run script at the end of each tape. The device name and the
197 current volume number are passed on the command line.
198 The script must return 0 if
200 should continue without asking the user to change the tape, 1 if
202 dump should continue but ask the user to change the tape.
203 Any other exit code will cause
206 For security reasons,
208 reverts back to the real user ID and the real group ID before
211 Use Kerberos authentication to talk to remote tape servers. (Only
212 available if this option was enabled when
216 The user-supplied text string
218 is placed into the dump header, where tools like
223 Note that this label is limited
224 to be at most LBLSIZE (currently 16) characters, which must include
228 Enable the multi-volume feature. The name specified with
230 is treated as a prefix and
232 writes in sequence to <prefix>001, <prefix>002 etc. This can be
233 useful when dumping to files on an ext2 partition, in order to bypass
234 the 2GB file size limitation.
238 requires operator attention,
239 notify all operators in the group
241 by means similar to a
244 Attempt to calculate the amount of tape needed
245 at a particular density.
246 If this amount is exceeded,
248 prompts for a new tape.
249 It is recommended to be a bit conservative on this option.
250 The default tape length is 2300 feet.
253 Size estimate. Determine the amount of space
254 that is needed to perform the dump without
255 actually doing it, and display the estimated
256 number of bytes it will take. This is useful
257 with incremental dumps to determine how many
258 volumes of media will be needed.
260 Use the specified date as the starting time for the dump
261 instead of the time determined from looking in
265 is the same as that of
267 This option is useful for automated dump scripts that wish to
268 dump over a specific period of time.
271 option is mutually exclusive from the
277 after a successful dump.
280 is readable by people, consisting of one
281 free format record per line:
287 There may be only one entry per filesystem at each level.
290 may be edited to change any of the fields,
294 tells the operator what file systems need to be dumped.
295 This information is gleaned from the files
303 to print out, for each file system in
305 the most recent dump date and level,
306 and highlights those file systems that should be dumped.
309 option is set, all other options are ignored, and
315 but prints only those filesystems which need to be dumped.
319 requires operator intervention on these conditions:
324 disk read error (if there is more than a threshold of 32).
325 In addition to alerting all operators implied by the
329 interacts with the operator on
331 control terminal at times when
333 can no longer proceed,
334 or if something is grossly wrong.
339 be answered by typing
345 Since making a dump involves a lot of time and effort for full dumps,
347 checkpoints itself at the start of each tape volume.
348 If writing that volume fails for some reason,
351 with operator permission,
352 restart itself from the checkpoint
353 after the old tape has been rewound and removed,
354 and a new tape has been mounted.
357 tells the operator what is going on at periodic intervals,
358 including usually low estimates of the number of blocks to write,
359 the number of tapes it will take, the time to completion, and
360 the time to the tape change.
361 The output is verbose,
362 so that others know that the terminal
366 and will be for some time.
368 In the event of a catastrophic disk event, the time required
369 to restore all the necessary backup tapes or files to disk
370 can be kept to a minimum by staggering the incremental dumps.
371 An efficient method of staggering incremental dumps
372 to minimize the number of tapes follows:
373 .Bl -bullet -offset indent
375 Always start with a level 0 backup, for example:
376 .Bd -literal -offset indent
377 /sbin/dump -0u -f /dev/st0 /usr/src
380 This should be done at set intervals, say once a month or once every two months,
381 and on a set of fresh tapes that is saved forever.
383 After a level 0, dumps of active file
384 systems are taken on a daily basis,
385 using a modified Tower of Hanoi algorithm,
386 with this sequence of dump levels:
387 .Bd -literal -offset indent
388 3 2 5 4 7 6 9 8 9 9 ...
391 For the daily dumps, it should be possible to use a fixed number of tapes
392 for each day, used on a weekly basis.
393 Each week, a level 1 dump is taken, and
394 the daily Hanoi sequence repeats beginning with 3.
395 For weekly dumps, another fixed set of tapes per dumped file system is
396 used, also on a cyclical basis.
399 After several months or so, the daily and weekly tapes should get
400 rotated out of the dump cycle and fresh tapes brought in.
404 If no -f option was specified,
406 will use the device specified via
414 .Qq user@host:tapename .
416 The environment variable
418 will be used to determine the pathname of the remote
423 uses the contents of this variable to determine the name of the
424 remote shell command to use when doing remote backups (rsh, ssh etc.).
425 If this variable is not set,
427 will be used, but only root will be able to do remote backups.
429 .Bl -tag -width __DUMPDATES__ -compact
431 default tape unit to dump to
435 dump table: file systems and frequency
448 exits with zero status on success.
449 Startup errors are indicated with an exit code of 1;
450 abnormal termination is indicated with an exit code of 3.
452 It might be considered a bug that this version of dump can only handle ext2
453 filesystems. Specifically, it does not work with FAT filesystems.
455 Fewer than 32 read errors on the filesystem are ignored. If noticing
456 read errors is important, the output from dump can be parsed to look for lines
457 that contain the text 'read error'.
459 Each reel requires a new process, so parent processes for
460 reels already written just hang around until the entire tape
468 option does not report filesystems that have never been recorded
476 knew about the dump sequence,
477 kept track of the tapes scribbled on,
478 told the operator which tape to mount when,
479 and provided more assistance
480 for the operator running
484 cannot do remote backups without being run as root, due to its
486 Presently, it works if you set it setuid (like it used to be), but this
487 might constitute a security risk. Note that you can set RSH to use
488 a remote shell program instead.
492 backup suit was ported to Linux's Second Extended File System
493 by Remy Card <card@Linux.EU.Org>. He maintained the initial versions
494 of dump (up and including 0.4b4, released in january 1997).
496 Starting with 0.4b5, the new maintainer is Stelian Pop
502 backup suit is available from
504 http://dump.sourceforge.net
git.wh0rd.org / dump.git / blob