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33 .\" $Id: dump.8.in,v 1.11 2000/02/04 20:22:21 stelian Exp $
37 .Os "dump __VERSION__"
40 .Nd ext2 filesystem backup
43 .Op Fl 0123456789ackMnSu
54 .Op Fl 0123456789ackMnSu
70 option syntax is implemented for backward compatibility but
71 is not documented here.)
76 and determines which files
77 need to be backed up. These files
78 are copied to the given disk, tape or other
79 storage medium for safe keeping (see the
81 option below for doing remote backups).
82 A dump that is larger than the output medium is broken into
84 On most media the size is determined by writing until an
85 end-of-media indication is returned. This can be enforced
90 On media that cannot reliably return an end-of-media indication
91 (such as some cartridge tape drives),
92 each volume is of a fixed size;
93 the actual size is determined by the tape size, density and/or
94 block count options below.
95 By default, the same output file name is used for each volume
96 after prompting the operator to change media.
98 The following options are supported by
103 A level 0, full backup,
104 guarantees the entire file system is copied
108 A level number above 0,
113 copy all files new or modified since the
114 last dump of a lower level.
115 The default level is 9.
117 The number of 1 KB blocks per volume.
118 This option overrides the calculation of tape size
119 based on length and density.
122 Bypass all tape length considerations, and enforce writing
123 until an end-of-media indication is returned. This fits best
124 for most modern tape drives. Use of this option is particularly
125 recommended when appending to an existing tape, or using a tape
126 drive with hardware compression (where you can never be sure about
127 the compression ratio).
128 .It Fl b Ar blocksize
129 The number of kilobytes per dump record.
130 Since the IO system slices all requests into chunks of MAXBSIZE
131 (typically 64KB), it is not possible to use a larger blocksize
132 without having problems later with
136 will constrain writes to MAXBSIZE.
138 Change the defaults for use with a cartridge tape drive, with a density
139 of 8000 bpi, and a length of 1700 feet.
143 from the dump (you can use
145 to find the inode number for a file or directory).
151 only for dumps at or above the given
153 The default honor level is 1,
154 so that incremental backups omit such files
155 but full backups retain them.
159 The default is 1600BPI.
164 may be a special device file
169 (a floppy disk drive),
173 (the standard output).
174 Multiple file names may be given as a single argument separated by commas.
175 Each file will be used for one dump volume in the order listed;
176 if the dump requires more volumes than the number of names given,
177 the last file name will used for all remaining volumes after prompting
179 If the name of the file is of the form
184 writes to the named file on the remote host using
186 The default path name of the remote
189 .\" rmt path, is the path on the remote host
191 this can be overridden by the environment variable
194 Use Kerberos authentication to talk to remote tape servers. (Only
195 available if this option was enabled when
199 The user-supplied text string
201 is placed into the dump header, where tools like
206 Note that this label is limited
207 to be at most LBLSIZE (currently 16) characters, which must include
211 Enable the multi-volume feature. The name specified with
213 is treated as a prefix and
215 writes in sequence to <prefix>001, <prefix>002 etc. This can be
216 useful when dumping to files on an ext2 partition, in order to bypass
217 the 2GB file size limitation.
221 requires operator attention,
222 notify all operators in the group
224 by means similar to a
227 Attempt to calculate the amount of tape needed
228 at a particular density.
229 If this amount is exceeded,
231 prompts for a new tape.
232 It is recommended to be a bit conservative on this option.
233 The default tape length is 2300 feet.
236 Size estimate. Determine the amount of space
237 that is needed to perform the dump without
238 actually doing it, and display the estimated
239 number of bytes it will take. This is useful
240 with incremental dumps to determine how many
241 volumes of media will be needed.
243 Use the specified date as the starting time for the dump
244 instead of the time determined from looking in
248 is the same as that of
250 This option is useful for automated dump scripts that wish to
251 dump over a specific period of time.
254 option is mutually exclusive from the
260 after a successful dump.
263 is readable by people, consisting of one
264 free format record per line:
270 There may be only one entry per filesystem at each level.
273 may be edited to change any of the fields,
277 tells the operator what file systems need to be dumped.
278 This information is gleaned from the files
286 to print out, for each file system in
288 the most recent dump date and level,
289 and highlights those file systems that should be dumped.
292 option is set, all other options are ignored, and
298 but prints only those filesystems which need to be dumped.
302 requires operator intervention on these conditions:
307 disk read error (if there is more than a threshold of 32).
308 In addition to alerting all operators implied by the
312 interacts with the operator on
314 control terminal at times when
316 can no longer proceed,
317 or if something is grossly wrong.
322 be answered by typing
328 Since making a dump involves a lot of time and effort for full dumps,
330 checkpoints itself at the start of each tape volume.
331 If writing that volume fails for some reason,
334 with operator permission,
335 restart itself from the checkpoint
336 after the old tape has been rewound and removed,
337 and a new tape has been mounted.
340 tells the operator what is going on at periodic intervals,
341 including usually low estimates of the number of blocks to write,
342 the number of tapes it will take, the time to completion, and
343 the time to the tape change.
344 The output is verbose,
345 so that others know that the terminal
349 and will be for some time.
351 In the event of a catastrophic disk event, the time required
352 to restore all the necessary backup tapes or files to disk
353 can be kept to a minimum by staggering the incremental dumps.
354 An efficient method of staggering incremental dumps
355 to minimize the number of tapes follows:
356 .Bl -bullet -offset indent
358 Always start with a level 0 backup, for example:
359 .Bd -literal -offset indent
360 /sbin/dump -0u -f /dev/st0 /usr/src
363 This should be done at set intervals, say once a month or once every two months,
364 and on a set of fresh tapes that is saved forever.
366 After a level 0, dumps of active file
367 systems are taken on a daily basis,
368 using a modified Tower of Hanoi algorithm,
369 with this sequence of dump levels:
370 .Bd -literal -offset indent
371 3 2 5 4 7 6 9 8 9 9 ...
374 For the daily dumps, it should be possible to use a fixed number of tapes
375 for each day, used on a weekly basis.
376 Each week, a level 1 dump is taken, and
377 the daily Hanoi sequence repeats beginning with 3.
378 For weekly dumps, another fixed set of tapes per dumped file system is
379 used, also on a cyclical basis.
382 After several months or so, the daily and weekly tapes should get
383 rotated out of the dump cycle and fresh tapes brought in.
387 If no -f option was specified,
389 will use the device specified via
397 .Qq user@host:tapename .
399 The environment variable
401 will be used to determine the pathname of the remote
406 uses the contents of this variable to determine the name of the
407 remote shell command to use when doing remote backups (rsh, ssh etc.).
408 If this variable is not set,
410 will be used, but only root will be able to do remote backups.
412 .Bl -tag -width __DUMPDATES__ -compact
414 default tape unit to dump to
418 dump table: file systems and frequency
431 exits with zero status on success.
432 Startup errors are indicated with an exit code of 1;
433 abnormal termination is indicated with an exit code of 3.
435 It might be considered a bug that this version of dump can only handle ext2
436 filesystems. Specifically, it does not work with FAT filesystems.
438 Fewer than 32 read errors on the filesystem are ignored. If noticing
439 read errors is important, the output from dump can be parsed to look for lines
440 that contain the text 'read error'.
442 Each reel requires a new process, so parent processes for
443 reels already written just hang around until the entire tape
451 option does not report filesystems that have never been recorded
459 knew about the dump sequence,
460 kept track of the tapes scribbled on,
461 told the operator which tape to mount when,
462 and provided more assistance
463 for the operator running
467 cannot do remote backups without being run as root, due to its
469 Presently, it works if you set it setuid (like it used to be), but this
470 might constitute a security risk. Note that you can set RSH to use
471 a remote shell program instead.
475 backup suit was ported to Linux's Second Extended File System
476 by Remy Card <card@Linux.EU.Org>. He maintained the initial versions
477 of dump (up and including 0.4b4, released in january 1997).
479 Starting with 0.4b5, the new maintainer is Stelian Pop
485 backup suit is available from
487 http://dump.sourceforge.net