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33 .\" $Id: dump.8.in,v 1.15 2000/08/19 22:08:53 stelian Exp $
37 .Os "dump __VERSION__"
40 .Nd ext2 filesystem backup
43 .Op Fl 0123456789ackMnSu
47 .Op Fl e Ar inode number
56 .Op Fl 0123456789ackMnSu
60 .Op Fl e Ar inode number
74 option syntax is implemented for backward compatibility but
75 is not documented here.)
80 and determines which files
81 need to be backed up. These files
82 are copied to the given disk, tape or other
83 storage medium for safe keeping (see the
85 option below for doing remote backups).
86 A dump that is larger than the output medium is broken into
88 On most media the size is determined by writing until an
89 end-of-media indication is returned. This can be enforced
94 On media that cannot reliably return an end-of-media indication
95 (such as some cartridge tape drives),
96 each volume is of a fixed size;
97 the actual size is determined by the tape size, density and/or
98 block count options below.
99 By default, the same output file name is used for each volume
100 after prompting the operator to change media.
102 The following options are supported by
107 A level 0, full backup,
108 guarantees the entire file system is copied
112 A level number above 0,
117 copy all files new or modified since the
118 last dump of a lower level.
119 The default level is 9.
121 The number of 1 KB blocks per volume.
122 This option overrides the calculation of tape size
123 based on length and density.
126 Bypass all tape length considerations, and enforce writing
127 until an end-of-media indication is returned. This fits best
128 for most modern tape drives. Use of this option is particularly
129 recommended when appending to an existing tape, or using a tape
130 drive with hardware compression (where you can never be sure about
131 the compression ratio).
132 .It Fl b Ar blocksize
133 The number of kilobytes per dump record.
134 Since the IO system slices all requests into chunks of MAXBSIZE
135 (typically 64KB), it is not possible to use a larger blocksize
136 without having problems later with
140 will constrain writes to MAXBSIZE.
141 The default blocksize is 10.
143 Change the defaults for use with a cartridge tape drive, with a density
144 of 8000 bpi, and a length of 1700 feet.
148 from the dump (you can use
150 to find the inode number for a file or directory).
156 only for dumps at or above the given
158 The default honor level is 1,
159 so that incremental backups omit such files
160 but full backups retain them.
164 The default is 1600BPI.
169 may be a special device file
174 (a floppy disk drive),
178 (the standard output).
179 Multiple file names may be given as a single argument separated by commas.
180 Each file will be used for one dump volume in the order listed;
181 if the dump requires more volumes than the number of names given,
182 the last file name will used for all remaining volumes after prompting
184 If the name of the file is of the form
189 writes to the named file on the remote host using
191 The default path name of the remote
194 .\" rmt path, is the path on the remote host
196 this can be overridden by the environment variable
199 Run script at the end of each tape. The device name and the
200 current volume number are passed on the command line.
201 The script must return 0 if
203 should continue without asking the user to change the tape, 1 if
205 dump should continue but ask the user to change the tape.
206 Any other exit code will cause
209 For security reasons,
211 reverts back to the real user ID and the real group ID before
214 Use Kerberos authentication to talk to remote tape servers. (Only
215 available if this option was enabled when
219 The user-supplied text string
221 is placed into the dump header, where tools like
226 Note that this label is limited
227 to be at most LBLSIZE (currently 16) characters, which must include
231 Enable the multi-volume feature. The name specified with
233 is treated as a prefix and
235 writes in sequence to <prefix>001, <prefix>002 etc. This can be
236 useful when dumping to files on an ext2 partition, in order to bypass
237 the 2GB file size limitation.
241 requires operator attention,
242 notify all operators in the group
244 by means similar to a
247 Attempt to calculate the amount of tape needed
248 at a particular density.
249 If this amount is exceeded,
251 prompts for a new tape.
252 It is recommended to be a bit conservative on this option.
253 The default tape length is 2300 feet.
256 Size estimate. Determine the amount of space
257 that is needed to perform the dump without
258 actually doing it, and display the estimated
259 number of bytes it will take. This is useful
260 with incremental dumps to determine how many
261 volumes of media will be needed.
263 Use the specified date as the starting time for the dump
264 instead of the time determined from looking in
268 is the same as that of
270 This option is useful for automated dump scripts that wish to
271 dump over a specific period of time.
274 option is mutually exclusive from the
280 after a successful dump.
283 is readable by people, consisting of one
284 free format record per line:
290 There may be only one entry per filesystem at each level.
293 may be edited to change any of the fields,
297 tells the operator what file systems need to be dumped.
298 This information is gleaned from the files
306 to print out, for each file system in
308 the most recent dump date and level,
309 and highlights those file systems that should be dumped.
312 option is set, all other options are ignored, and
318 but prints only those filesystems which need to be dumped.
322 requires operator intervention on these conditions:
327 disk read error (if there is more than a threshold of 32).
328 In addition to alerting all operators implied by the
332 interacts with the operator on
334 control terminal at times when
336 can no longer proceed,
337 or if something is grossly wrong.
342 be answered by typing
348 Since making a dump involves a lot of time and effort for full dumps,
350 checkpoints itself at the start of each tape volume.
351 If writing that volume fails for some reason,
354 with operator permission,
355 restart itself from the checkpoint
356 after the old tape has been rewound and removed,
357 and a new tape has been mounted.
360 tells the operator what is going on at periodic intervals,
361 including usually low estimates of the number of blocks to write,
362 the number of tapes it will take, the time to completion, and
363 the time to the tape change.
364 The output is verbose,
365 so that others know that the terminal
369 and will be for some time.
371 In the event of a catastrophic disk event, the time required
372 to restore all the necessary backup tapes or files to disk
373 can be kept to a minimum by staggering the incremental dumps.
374 An efficient method of staggering incremental dumps
375 to minimize the number of tapes follows:
376 .Bl -bullet -offset indent
378 Always start with a level 0 backup, for example:
379 .Bd -literal -offset indent
380 /sbin/dump -0u -f /dev/st0 /usr/src
383 This should be done at set intervals, say once a month or once every two months,
384 and on a set of fresh tapes that is saved forever.
386 After a level 0, dumps of active file
387 systems are taken on a daily basis,
388 using a modified Tower of Hanoi algorithm,
389 with this sequence of dump levels:
390 .Bd -literal -offset indent
391 3 2 5 4 7 6 9 8 9 9 ...
394 For the daily dumps, it should be possible to use a fixed number of tapes
395 for each day, used on a weekly basis.
396 Each week, a level 1 dump is taken, and
397 the daily Hanoi sequence repeats beginning with 3.
398 For weekly dumps, another fixed set of tapes per dumped file system is
399 used, also on a cyclical basis.
402 After several months or so, the daily and weekly tapes should get
403 rotated out of the dump cycle and fresh tapes brought in.
407 If no -f option was specified,
409 will use the device specified via
417 .Qq user@host:tapename .
419 The environment variable
421 will be used to determine the pathname of the remote
426 uses the contents of this variable to determine the name of the
427 remote shell command to use when doing remote backups (rsh, ssh etc.).
428 If this variable is not set,
430 will be used, but only root will be able to do remote backups.
432 .Bl -tag -width __DUMPDATES__ -compact
434 default tape unit to dump to
438 dump table: file systems and frequency
451 exits with zero status on success.
452 Startup errors are indicated with an exit code of 1;
453 abnormal termination is indicated with an exit code of 3.
455 It might be considered a bug that this version of dump can only handle ext2
456 filesystems. Specifically, it does not work with FAT filesystems.
458 Fewer than 32 read errors on the filesystem are ignored. If noticing
459 read errors is important, the output from dump can be parsed to look for lines
460 that contain the text 'read error'.
462 Each reel requires a new process, so parent processes for
463 reels already written just hang around until the entire tape
471 option does not report filesystems that have never been recorded
479 knew about the dump sequence,
480 kept track of the tapes scribbled on,
481 told the operator which tape to mount when,
482 and provided more assistance
483 for the operator running
487 cannot do remote backups without being run as root, due to its
489 Presently, it works if you set it setuid (like it used to be), but this
490 might constitute a security risk. Note that you can set RSH to use
491 a remote shell program instead.
495 backup suit was ported to Linux's Second Extended File System
496 by Remy Card <card@Linux.EU.Org>. He maintained the initial versions
497 of dump (up and including 0.4b4, released in january 1997).
499 Starting with 0.4b5, the new maintainer is Stelian Pop
505 backup suit is available from
507 http://dump.sourceforge.net