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33 .\" @(#)dump.8 8.3 (Berkeley) 5/1/95
45 .Op Fl 0123456789acknu
60 option syntax is implemented for backward compatibility, but
61 is not documented here.)
66 and determines which 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 and 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.
89 The following options are supported by
94 A level 0, full backup,
95 guarantees the entire file system is copied
99 A level number above 0,
102 copy all files new or modified since the
103 last dump of any lower level.
104 The default level is 0.
106 The number of 1 KB blocks per volume.
107 This option overrides the calculation of tape size
108 based on length and density.
111 Bypass all tape length considerations, and enforce writing
112 until an end-of-media indication is returned. This fits best
113 for most modern tape drives. Use of this option is particularly
114 recommended when appending to an existing tape, or using a tape
115 drive with hardware compression (where you can never be sure about
116 the compression ratio).
117 .It Fl b Ar blocksize
118 The number of kilobytes per dump record.
120 Change the defaults for use with a cartridge tape drive, with a density
121 of 8000 bpi, and a length of 1700 feet.
127 only for dumps at or above the given
129 The default honor level is 1,
130 so that incremental backups omit such files
131 but full backups retain them.
135 The default is 1600BPI.
140 may be a special device file
145 (a floppy disk drive),
149 (the standard output).
150 Multiple file names may be given as a single argument separated by commas.
151 Each file will be used for one dump volume in the order listed;
152 if the dump requires more volumes than the number of names given,
153 the last file name will used for all remaining volumes after prompting
155 If the name of the file is of the form
160 writes to the named file on the remote host using
162 The default path name of the remote
165 .\" rmt path, is the path on the remote host
167 this can be overridden by the environment variable
170 Use Kerberos authentication to talk to remote tape servers. (Only
171 available if this option was enabled when
177 requires operator attention,
178 notify all operators in the group
180 by means similar to a
183 Attempt to calculate the amount of tape needed
184 at a particular density.
185 If this amount is exceeded,
187 prompts for a new tape.
188 It is recommended to be a bit conservative on this option.
189 The default tape length is 2300 feet.
192 Use the specified date as the starting time for the dump
193 instead of the time determined from looking in
195 The format of date is the same as that of
197 This option is useful for automated dump scripts that wish to
198 dump over a specific period of time.
201 option is mutually exclusive from the
207 after a successful dump.
210 is readable by people, consisting of one
211 free format record per line:
217 There may be only one entry per filesystem at each level.
220 may be edited to change any of the fields,
224 tells the operator what file systems need to be dumped.
225 This information is gleaned from the files
233 to print out, for each file system in
235 the most recent dump date and level,
236 and highlights those file systems that should be dumped.
239 option is set, all other options are ignored, and
243 Is like W, but prints only those filesystems which need to be dumped.
247 requires operator intervention on these conditions:
252 disk read error (if there are more than a threshold of 32).
253 In addition to alerting all operators implied by the
257 interacts with the operator on
259 control terminal at times when
261 can no longer proceed,
262 or if something is grossly wrong.
267 be answered by typing
273 Since making a dump involves a lot of time and effort for full dumps,
275 checkpoints itself at the start of each tape volume.
276 If writing that volume fails for some reason,
279 with operator permission,
280 restart itself from the checkpoint
281 after the old tape has been rewound and removed,
282 and a new tape has been mounted.
285 tells the operator what is going on at periodic intervals,
286 including usually low estimates of the number of blocks to write,
287 the number of tapes it will take, the time to completion, and
288 the time to the tape change.
289 The output is verbose,
290 so that others know that the terminal
294 and will be for some time.
296 In the event of a catastrophic disk event, the time required
297 to restore all the necessary backup tapes or files to disk
298 can be kept to a minimum by staggering the incremental dumps.
299 An efficient method of staggering incremental dumps
300 to minimize the number of tapes follows:
301 .Bl -bullet -offset indent
303 Always start with a level 0 backup, for example:
304 .Bd -literal -offset indent
305 /sbin/dump -0u -f /dev/nrsa0 /usr/src
308 This should be done at set intervals, say once a month or once every two months,
309 and on a set of fresh tapes that is saved forever.
311 After a level 0, dumps of active file
312 systems are taken on a daily basis,
313 using a modified Tower of Hanoi algorithm,
314 with this sequence of dump levels:
315 .Bd -literal -offset indent
316 3 2 5 4 7 6 9 8 9 9 ...
319 For the daily dumps, it should be possible to use a fixed number of tapes
320 for each day, used on a weekly basis.
321 Each week, a level 1 dump is taken, and
322 the daily Hanoi sequence repeats beginning with 3.
323 For weekly dumps, another fixed set of tapes per dumped file system is
324 used, also on a cyclical basis.
327 After several months or so, the daily and weekly tapes should get
328 rotated out of the dump cycle and fresh tapes brought in.
330 The environment variable
332 will be used to determine the pathname of the remote
336 .Bl -tag -width /etc/dumpdates -compact
338 default tape unit to dump to
339 .It Pa /etc/dumpdates
342 dump table: file systems and frequency
354 Dump exits with zero status on success.
355 Startup errors are indicated with an exit code of 1;
356 abnormal termination is indicated with an exit code of 3.
358 Fewer than 32 read errors on the filesystem are ignored.
360 Each reel requires a new process, so parent processes for
361 reels already written just hang around until the entire tape
366 slices all requests into chunks of 64 KB. Therefore, it is
367 impossible to use a larger tape blocksize, so
369 will prevent this from happening.
376 options does not report filesystems that have never been recorded
384 knew about the dump sequence,
385 kept track of the tapes scribbled on,
386 told the operator which tape to mount when,
387 and provided more assistance
388 for the operator running
392 cannot do remote backups without being run as root, due to its
393 security history. This will be fixed in a later version of
395 Presently, it works if you set it setuid (like it used to be), but this
396 might constitute a security risk.