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33 .\" @(#)dump.8 8.3 (Berkeley) 5/1/95
34 .\" $Id: dump.8.in,v 1.1 1999/10/11 13:08:07 stelian Exp $
41 .Nd ext2 filesystem backup
44 .Op Fl 0123456789acknu
55 .Op Fl 0123456789acknu
71 option syntax is implemented for backward compatibility but
72 is not documented here.)
77 and determines which files
78 need to be backed up. These files
79 are copied to the given disk, tape or other
80 storage medium for safe keeping (see the
82 option below for doing remote backups).
83 A dump that is larger than the output medium is broken into
85 On most media the size is determined by writing until an
86 end-of-media indication is returned. This can be enforced
91 On media that cannot reliably return an end-of-media indication
92 (such as some cartridge tape drives),
93 each volume is of a fixed size;
94 the actual size is determined by the tape size, density and/or
95 block count options below.
96 By default, the same output file name is used for each volume
97 after prompting the operator to change media.
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 the same or 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.
139 Change the defaults for use with a cartridge tape drive, with a density
140 of 8000 bpi, and a length of 1700 feet.
146 only for dumps at or above the given
148 The default honor level is 1,
149 so that incremental backups omit such files
150 but full backups retain them.
154 The default is 1600BPI.
159 may be a special device file
164 (a floppy disk drive),
168 (the standard output).
169 Multiple file names may be given as a single argument separated by commas.
170 Each file will be used for one dump volume in the order listed;
171 if the dump requires more volumes than the number of names given,
172 the last file name will used for all remaining volumes after prompting
174 If the name of the file is of the form
179 writes to the named file on the remote host using
181 The default path name of the remote
184 .\" rmt path, is the path on the remote host
186 this can be overridden by the environment variable
189 Use Kerberos authentication to talk to remote tape servers. (Only
190 available if this option was enabled when
194 The user-supplied text string
196 is placed into the dump header, where tools like
201 Note that this label is limited
202 to be at most LBLSIZE (currently 16) characters, which must include
208 requires operator attention,
209 notify all operators in the group
211 by means similar to a
214 Attempt to calculate the amount of tape needed
215 at a particular density.
216 If this amount is exceeded,
218 prompts for a new tape.
219 It is recommended to be a bit conservative on this option.
220 The default tape length is 2300 feet.
223 Use the specified date as the starting time for the dump
224 instead of the time determined from looking in
228 is the same as that of
230 This option is useful for automated dump scripts that wish to
231 dump over a specific period of time.
234 option is mutually exclusive from the
240 after a successful dump.
243 is readable by people, consisting of one
244 free format record per line:
250 There may be only one entry per filesystem at each level.
253 may be edited to change any of the fields,
257 tells the operator what file systems need to be dumped.
258 This information is gleaned from the files
266 to print out, for each file system in
268 the most recent dump date and level,
269 and highlights those file systems that should be dumped.
272 option is set, all other options are ignored, and
278 but prints only those filesystems which need to be dumped.
282 requires operator intervention on these conditions:
287 disk read error (if there is more than a threshold of 32).
288 In addition to alerting all operators implied by the
292 interacts with the operator on
294 control terminal at times when
296 can no longer proceed,
297 or if something is grossly wrong.
302 be answered by typing
308 Since making a dump involves a lot of time and effort for full dumps,
310 checkpoints itself at the start of each tape volume.
311 If writing that volume fails for some reason,
314 with operator permission,
315 restart itself from the checkpoint
316 after the old tape has been rewound and removed,
317 and a new tape has been mounted.
320 tells the operator what is going on at periodic intervals,
321 including usually low estimates of the number of blocks to write,
322 the number of tapes it will take, the time to completion, and
323 the time to the tape change.
324 The output is verbose,
325 so that others know that the terminal
329 and will be for some time.
331 In the event of a catastrophic disk event, the time required
332 to restore all the necessary backup tapes or files to disk
333 can be kept to a minimum by staggering the incremental dumps.
334 An efficient method of staggering incremental dumps
335 to minimize the number of tapes follows:
336 .Bl -bullet -offset indent
338 Always start with a level 0 backup, for example:
339 .Bd -literal -offset indent
340 /sbin/dump -0u -f /dev/st0 /usr/src
343 This should be done at set intervals, say once a month or once every two months,
344 and on a set of fresh tapes that is saved forever.
346 After a level 0, dumps of active file
347 systems are taken on a daily basis,
348 using a modified Tower of Hanoi algorithm,
349 with this sequence of dump levels:
350 .Bd -literal -offset indent
351 3 2 5 4 7 6 9 8 9 9 ...
354 For the daily dumps, it should be possible to use a fixed number of tapes
355 for each day, used on a weekly basis.
356 Each week, a level 1 dump is taken, and
357 the daily Hanoi sequence repeats beginning with 3.
358 For weekly dumps, another fixed set of tapes per dumped file system is
359 used, also on a cyclical basis.
362 After several months or so, the daily and weekly tapes should get
363 rotated out of the dump cycle and fresh tapes brought in.
367 If no -f option was specified,
369 will use the device specified via
377 .Qq user@host:tapename .
379 The environment variable
381 will be used to determine the pathname of the remote
385 .Bl -tag -width __DUMPDATES__ -compact
387 default tape unit to dump to
391 dump table: file systems and frequency
404 exits with zero status on success.
405 Startup errors are indicated with an exit code of 1;
406 abnormal termination is indicated with an exit code of 3.
408 It might be considered a bug that this version of dump can only handle ext2
409 filesystems. Specifically, it does not work with FAT filesystems.
411 Fewer than 32 read errors on the filesystem are ignored. If noticing
412 read errors is important, the output from dump can be parsed to look for lines
413 that contain the text 'read error'.
415 Each reel requires a new process, so parent processes for
416 reels already written just hang around until the entire tape
424 option does not report filesystems that have never been recorded
432 knew about the dump sequence,
433 kept track of the tapes scribbled on,
434 told the operator which tape to mount when,
435 and provided more assistance
436 for the operator running
440 cannot do remote backups without being run as root, due to its
441 security history. This will be fixed in a later version of
443 Presently, it works if you set it setuid (like it used to be), but this
444 might constitute a security risk.
448 backup suit was ported to Linux's Second Extended File System
449 by Remy Card <card@Linux.EU.Org>. He maintained the initial versions
450 of dump (up and including 0.4b4, released in january 1997).
452 Starting with 0.4b5, the new maintainer is Stelian Pop
458 backup suit is available for anonymous ftp from tsx-11.mit.edu
459 in /pub/linux/ALPHA/ext2fs (development versions) or
460 /pub/linux/packages/ext2fs (stable versions).
462 An alternate downloading location is http://perso.cybercable.fr/pop/dump.