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33 .\" $Id: dump.8.in,v 1.47 2003/01/10 10:31:10 stelian Exp $
35 .TH DUMP 8 "version __VERSION__ of __DATE__" BSD "System management commands"
37 dump \- ext2/3 filesystem backup
40 [\fB\-0123456789ackMnqSuv\fR]
42 [\fB\-B \fIrecords\fR]
43 [\fB\-b \fIblocksize\fR]
44 [\fB\-d \fIdensity\fR]
45 [\fB\-e \fIinode numbers\fR]
50 [\fB\-I \fInr errors\fR]
51 [\fB\-j\fIcompression level\fR]
56 [\fB\-z\fIcompression level\fR]
60 [\fB\-W \fR| \fB\-w\fR]
62 (The 4.3BSD option syntax is implemented for backward compatibility but is not
66 examines files on an ext2/3 filesystem and determines which files need to be
67 backed up. These files are copied to the given disk, tape or other storage
68 medium for safe keeping (see the
70 option below for doing remote backups). A dump that is larger than the output
71 medium is broken into multiple volumes. On most media the size is determined by
72 writing until an end-of-media indication is returned.
74 On media that cannot reliably return an end-of-media indication (such as some
75 cartridge tape drives), each volume is of a fixed size; the actual size is
76 determined by specifying cartridge media, or via the tape size, density and/or
77 block count options below. By default, the same output file name is used for
78 each volume after prompting the operator to change media.
81 is either a mountpoint of a filesystem or a list of files and directories to be
82 backed up as a subset of a filesystem. In the former case, either the path to a
83 mounted filesystem or the device of an unmounted filesystem can be used. In the
84 latter case, certain restrictions are placed on the backup:
86 is not allowed, the only dump level that is supported is
88 and all the files and directories must reside on the same filesystem.
90 The following options are supported by
94 Dump levels. A level 0, full backup, guarantees the entire file system is
95 copied (but see also the
97 option below). A level number above 0, incremental backup, tells
100 copy all files new or modified since the last dump of a lower level. The
104 \*(lqauto-size\*(rq. Bypass all tape length calculations, and write until an
105 end-of-media indication is returned. This works best for most modern tape
106 drives, and is the default. Use of this option is particularly recommended when
107 appending to an existing tape, or using a tape drive with hardware compression
108 (where you can never be sure about the compression ratio).
110 .BI \-A " archive_file"
111 Archive a dump table-of-contents in the specified
115 to determine whether a file is in the dump file that is being restored.
118 The number of kilobytes per dump record. The default blocksize is 10
119 and the maximal value is 1024.
120 Note however that, since the IO system slices all requests into chunks
123 (which can be as low as 64kB), you can experience problems with
127 when using a higher value, depending on your kernel and/or libC versions.
130 The number of 1 kB blocks per volume. Not normally required, as
132 can detect end-of-media. When the specified size is reached,
134 waits for you to change the volume. This option overrides the calculation of
135 tape size based on length and density. If compression is on this limits the
136 size of the compressed output per volume.
139 Change the defaults for use with a cartridge tape drive, with a density of 8000
140 bpi, and a length of 1700 feet. Specifying a cartridge drive overrides the
141 end-of-media detection.
146 The default is 1600BPI. Specifying a tape density overrides the end-of-media
154 parameter is a comma separated list of inode numbers (you can use
156 to find the inode number for a file or directory).
159 Read list of inodes to be excluded from the dump from the text file
163 should be an ordinary file containing inode numbers separated by newlines.
169 may be a special device file like
173 (a floppy disk drive), an ordinary file, or
175 (the standard output). Multiple file names may be given as a single argument
176 separated by commas. Each file will be used for one dump volume in the order
177 listed; if the dump requires more volumes than the number of names given,
178 the last file name will used for all remaining volumes after prompting for
179 media changes. 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
190 this can be overridden by the environment variable
194 Run script at the end of each tape (except for the last one).
195 The device name and the current volume number are passed on the
196 command line. The script must return 0 if
198 should continue without asking the user to change the tape, 1 if
200 should continue but ask the user to change the tape. Any other exit code will
203 to abort. For security reasons,
205 reverts back to the real user ID and the real group ID before running the
213 only for dumps at or above the given
215 The default honor level is 1, so that incremental backups omit such files but
216 full backups retain them.
221 will ignore the first 32 read errors on the file system before asking for
222 operator intervention. You can change this using this flag to any value. This
223 is useful when running
225 on an active filesystem where read errors simply indicate an inconsistency
226 between the mapping and dumping passes.
228 A value of 0 means that all read errors will be ignored.
230 .BI \-j "compression level"
231 Compress every block to be written on the tape using bzlib library. This option
232 will work only when dumping to a file or pipe or, when dumping to a tape drive,
233 if the tape drive is capable of writing variable length blocks. You will need
234 at least the 0.4b24 version of
236 in order to extract compressed tapes. Tapes written using compression will not
237 be compatible with the BSD tape format. The (optional) parameter specifies the
238 compression level bzlib will use. The default compression level is 2. If the
239 optional parameter is specified, there should be no white space between the
240 option letter and the parameter.
243 Use Kerberos authentication to talk to remote tape servers. (Only available if
244 this option was enabled when
249 The user-supplied text string
251 is placed into the dump header, where tools like
255 can access it. Note that this label is limited to be at most
257 (currently 16) characters, which must include the terminating \e0.
260 If this flag is specified,
262 will optimise the output for inodes having been changed but not modified since
263 the last dump ('changed' and 'modified' have the meaning defined in
267 will save only the metadata, instead of saving the entire inode contents.
268 Inodes which are either directories or have been modified since the last dump
269 are saved in a regular way. Uses of this flag must be consistent, meaning that
270 either every dump in an incremental dump set have the flag, or no one has it.
272 Tapes written using such 'metadata only' inodes will not be compatible with the
273 BSD tape format or older versions of
277 Enable the multi-volume feature. The name specified with
279 is treated as a prefix and
281 writes in sequence to
282 .I <prefix>001, <prefix>002
283 etc. This can be useful when dumping to files on an ext2 partition, in order to
284 bypass the 2GB file size limitation.
289 requires operator attention, notify all operators in the group
291 by means similar to a
297 abort immediately whenever operator attention is required, without prompting in
298 case of write errors, tape changes etc.
301 Enable the Quick File Access support. Tape positions for each inode are stored
306 (if called with parameter
308 and the filename) to directly position the tape at the file
310 is currently working on. This saves hours when restoring single files from
311 large backups, saves the tapes and the drive's head.
313 It is recommended to set up the st driver to return logical tape positions
314 rather than physical before calling
318 Since not all tape devices support physical tape positions those tape devices
319 return an error during
321 when the st driver is set to the default physical setting. Please see the
327 man page, on how to set the driver to return logical tape positions.
333 always make sure the st driver is set to return the same type of tape position
334 used during the call to
340 This option can be used when dumping to local tapes (see above) or to local
344 Attempt to calculate the amount of tape needed at a particular density. If this
347 prompts for a new tape. It is recommended to be a bit conservative on this
348 option. The default tape length is 2300 feet. Specifying the tape size
349 overrides end-of-media detection.
352 Size estimate. Determine the amount of space that is needed to perform the dump
353 without actually doing it, and display the estimated number of bytes it will
354 take. This is useful with incremental dumps to determine how many volumes of
355 media will be needed.
358 Use the specified date as the starting time for the dump instead of the time
359 determined from looking in
363 is the same as that of
365 This option is useful for automated dump scripts that wish to dump over a
366 specific period of time. The
368 option is mutually exclusive from the
375 after a successful dump. The format of
377 is readable by people, consisting of one free format record per line:
378 filesystem name, increment level and
380 format dump date. There may be only one entry per filesystem at each level. The
383 may be edited to change any of the fields, if necessary.
390 to print extra information which could be helpful in debug sessions.
394 tells the operator what file systems need to be dumped. This information is
395 gleaned from the files
403 to print out, for all file systems in
405 and regognized file systems in
407 the most recent dump date and level, and highlights those that should be
410 option is set, all other options are ignored, and
417 but prints only recognized filesystems in
419 which need to be dumped.
421 .BI \-z "compression level"
422 Compress every block to be written on the tape using zlib library. This option
423 will work only when dumping to a file or pipe or, when dumping to a tape drive,
424 if the tape drive is capable of writing variable length blocks. You will need
425 at least the 0.4b22 version of
427 in order to extract compressed tapes. Tapes written using compression will not
428 be compatible with the BSD tape format. The (optional) parameter specifies the
429 compression level zlib will use. The default compression level is 2. If the
430 optional parameter is specified, there should be no white space between the
431 option letter and the parameter.
434 requires operator intervention on these conditions: end of tape, end of dump,
435 tape write error, tape open error or disk read error (if there is more than a
436 threshold of nr errors). In addition to alerting all operators implied by the
440 interacts with the operator on dump's control terminal at times when
442 can no longer proceed, or if something is grossly wrong. All questions
446 be answered by typing \*(lqyes\*(rq or \*(lqno\*(rq, appropriately.
448 Since making a dump involves a lot of time and effort for full dumps,
450 checkpoints itself at the start of each tape volume. If writing that volume
451 fails for some reason,
453 will, with operator permission, restart itself from the checkpoint after the
454 old tape has been rewound and removed, and a new tape has been mounted.
457 tells the operator what is going on at periodic intervals, including usually
458 low estimates of the number of blocks to write, the number of tapes it will
459 take, the time to completion, and the time to the tape change. The output is
460 verbose, so that others know that the terminal controlling
462 is busy, and will be for some time.
464 In the event of a catastrophic disk event, the time required to restore all the
465 necessary backup tapes or files to disk can be kept to a minimum by staggering
466 the incremental dumps. An efficient method of staggering incremental dumps to
467 minimize the number of tapes follows:
469 Always start with a level 0 backup, for example:
471 .B /sbin/dump -0u -f /dev/st0 /usr/src
474 This should be done at set intervals, say once a month or once every two months,
475 and on a set of fresh tapes that is saved forever.
477 After a level 0, dumps of active file systems are taken on a daily basis, using
478 a modified Tower of Hanoi algorithm, with this sequence of dump levels:
480 .B 3 2 5 4 7 6 9 8 9 9 ...
483 For the daily dumps, it should be possible to use a fixed number of tapes for
484 each day, used on a weekly basis. Each week, a level 1 dump is taken, and the
485 daily Hanoi sequence repeats beginning with 3. For weekly dumps, another fixed
486 set of tapes per dumped file system is used, also on a cyclical basis.
488 After several months or so, the daily and weekly tapes should get rotated out
489 of the dump cycle and fresh tapes brought in.
495 option was specified,
497 will use the device specified via
505 .IR user@host:tapename .
508 The environment variable
510 will be used to determine the pathname of the remote
516 uses the contents of this variable to determine the name of the remote shell
517 command to use when doing remote backups (rsh, ssh etc.). If this variable is
520 will be used, but only root will be able to do remote backups.
524 default tape unit to dump to
530 dump table: file systems and frequency
543 exits with zero status on success. Startup errors are indicated with an exit
544 code of 1; abnormal termination is indicated with an exit code of 3.
546 It might be considered a bug that this version of dump can only handle ext2/3
547 filesystems. Specifically, it does not work with FAT filesystems.
549 Fewer than 32 read errors (change this with
551 on the filesystem are ignored. If noticing read errors is important, the output
552 from dump can be parsed to look for lines that contain the text 'read error'.
554 When a read error occurs,
556 prints out the corresponding physical disk block and sector number and the
557 ext2/3 logical block number. It doesn't print out the corresponing file name or
558 even the inode number. The user has to use
566 number printed out by
568 into an inode number, then into a file name.
570 Each reel requires a new process, so parent processes for reels already written
571 just hang around until the entire tape is written.
573 The estimated number of tapes is not correct if compression is on.
577 knew about the dump sequence, kept track of the tapes scribbled on, told the
578 operator which tape to mount when, and provided more assistance for the
583 cannot do remote backups without being run as root, due to its security history.
584 Presently, it works if you set it setuid (like it used to be), but this might
585 constitute a security risk. Note that you can set
587 to use a remote shell program instead.
591 backup suite was ported to Linux's Second Extended File System by Remy Card
592 <card@Linux.EU.Org>. He maintained the initial versions of
594 (up and including 0.4b4, released in january 1997).
596 Starting with 0.4b5, the new maintainer is Stelian Pop <stelian@popies.net>.
600 backup suite is available from <http://dump.sourceforge.net>
605 .B Version 6 AT&T UNIX.