1xfsdump(8) System Manager's Manual xfsdump(8)
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6 xfsdump - XFS filesystem incremental dump utility
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9 xfsdump -h
10 xfsdump [ options ] -f dest [ -f dest ... ] filesystem
11 xfsdump [ options ] - filesystem
12 xfsdump -I [ subopt=value ... ]
13
15 xfsdump backs up files and their attributes in a filesystem. The files
16 are dumped to storage media, a regular file, or standard output.
17 Options allow the operator to have all files dumped, just files that
18 have changed since a previous dump, or just files contained in a list
19 of pathnames.
20 The xfsrestore(8) utility re-populates a filesystem with the contents
22 of the dump.
23 Each invocation of xfsdump dumps just one filesystem. That invocation
25 is termed a dump session. The dump session splits the filesystem into
26 one or more dump streams, one per destination. The split is done in
27 filesystem inode number (ino) order, at boundaries selected to equalize
28 the size of each stream. Furthermore, the breakpoints between streams
29 may be in the middle of very large files (at extent boundaries) if nec‐
30 essary to achieve reasonable stream size equalization. Each dump
31 stream can span several media objects, and a single media object can
32 contain several dump streams. The typical media object is a tape car‐
33 tridge. The media object records the dump stream as one or more media
34 files. A media file is a self-contained partial dump, intended to min‐
35 imize the impact of media dropouts on the entire dump stream at the
36 expense of increasing the time required to complete the dump. By
37 default only one media file is written unless a media file size is
38 specified using the -d option. Other techniques, such as making a sec‐
39 ond copy of the dump image, provide more protection against media fail‐
40 ures than multiple media files will.
41 However, the current implementation in Linux only supports one destina‐
43 tion and running single threaded. Therefore, the above comments regard‐
44 ing multiple streams describe the possible future capabilities.
45 xfsdump maintains an online dump inventory in /var/lib/xfsdump/inven‐
47 tory. The -I option displays the inventory contents hierarchically.
48 The levels of the hierarchy are: filesystem, dump session, stream, and
49 media file.
50 The options to xfsdump are:
52 -a Specifies that files for which the Data Migration Facility (DMF)
54 has complete offline copies (dual-state files) be treated as if
55 they were offline (OFL). This means that the file data will not
56 be dumped by xfsdump, resulting in a smaller dump file. If the
57 file is later restored the file data is still accessible through
58 DMF. If both '-a option' and '-z option' are specified, the '-a
59 option' takes precedence (see '-z option' below).
60 -b blocksize
62 Specifies the blocksize, in bytes, to be used for the dump. The
63 same blocksize must be specified to restore the tape. If the -m
64 option is not used, then -b does not need to be specified.
65 Instead, a default blocksize of 1Mb will be used.
66 -c progname
68 Use the specified program to alert the operator when a media
69 change is required. The alert program is typically a script to
70 send a mail or flash a window to draw the operator's attention.
71 -d filesize
73 Specifies the size, in megabytes, of dump media files. If not
74 specified, xfsdump will dump data to tape using a single media
75 file per media object. The specified media file size may need to
76 be adjusted if, for example, xfsdump cannot fit a media file onto
77 a single tape.
78 -e Allow files to be excluded from the dump. This will cause xfsdump
80 to skip files which have the "no dump" file attribute set. See the
81 "Excluding individual files" section below for details on setting
82 this file attribute. Files with an extended attribute named
83 "SGI_XFSDUMP_SKIP_FILE" will also be skipped, however this method
84 is deprecated and xfsdump will stop checking for it in a future
85 version.
86 -f dest [ -f dest ... ]
88 Specifies a dump destination. A dump destination can be the path‐
89 name of a device (such as a tape drive), a regular file or a
90 remote tape drive (see rmt(8)). This option must be omitted if
91 the standard output option (a lone - preceding the source filesys‐
92 tem specification) is specified.
93 -l level
95 Specifies a dump level of 0 to 9. The dump level determines the
96 base dump to which this dump is relative. The base dump is the
97 most recent dump at a lesser level. A level 0 dump is absolute -
98 all files are dumped. A dump level where 1 <= level <= 9 is
99 referred to as an incremental dump. Only files that have been
100 changed since the base dump are dumped. Subtree dumps (see the -s
101 option below) cannot be used as the base for incremental dumps.
102 -m Use the minimal tape protocol for non-scsi tape destinations or
104 remote tape destinations which are not scsi Linux tape drives nor
105 IRIX tape drives. This option cannot be used without specifying a
106 blocksize to be used (see -b option above).
107 -o Overwrite the tape. With this option, xfsdump does not read the
109 tape first to check the contents. This option may be used if xfs‐
110 dump is unable to determine the block size of a tape .
111 -p interval
113 Causes progress reports to be printed at the specified interval.
114 interval is given in seconds. The progress report indicates how
115 many files have been dumped, the total number of files to dump,
116 the percentage of data dumped, and the elapsed time.
117 -q Destination tape drive is a QIC tape. QIC tapes only use a 512
119 byte blocksize, for which xfsdump must make special allowances.
120 -s pathname [ -s pathname ... ]
122 Restricts the dump to files contained in the specified pathnames
123 (subtrees). A pathname must be relative to the mount point of the
124 filesystem. For example, if a filesystem is mounted at /d2, the
125 pathname argument for the directory /d2/users is ``users''. A
126 pathname can be a file or a directory; if it is a directory, the
127 entire hierarchy of files and subdirectories rooted at that direc‐
128 tory is dumped. Subtree dumps cannot be used as the base for
129 incremental dumps (see the -l option above).
130 -t file
132 Sets the dump time to the modification time of file rather than
133 using the current time. xfsdump uses the dump time to determine
134 what files need to be backed up during an incremental dump. This
135 option should be used when dumping snapshots so that the dump time
136 matches the time the snapshot was taken. Otherwise files modified
137 after a snapshot is taken may be skipped in the next incremental
138 dump.
139 -v verbosity
141 -v subsys=verbosity[,subsys=verbosity,...]
142 Specifies the level of detail used for messages displayed during
143 the course of the dump. The verbosity argument can be passed as
144 either a string or an integer. If passed as a string the following
145 values may be used: silent, verbose, trace, debug, or nitty. If
146 passed as an integer, values from 0-5 may be used. The values 0-4
147 correspond to the strings already listed. The value 5 can be used
148 to produce even more verbose debug output.
149 The first form of this option activates message logging across all
151 dump subsystems. The second form allows the message logging level
152 to be controlled on a per-subsystem basis. The two forms can be
153 combined (see the example below). The argument subsys can take one
154 of the following values: general, proc, drive, media, inventory,
155 inomap and excluded_files.
156 For example, to dump the root filesystem with tracing activated
158 for all subsystems:
159 # xfsdump -v trace -f /dev/tape /
161 To enable debug-level tracing for drive and media operations:
163 # xfsdump -v drive=debug,media=debug -f /dev/tape /
165 To enable tracing for all subsystems, and debug level tracing for
167 drive operations only:
168 # xfsdump -v trace,drive=debug -f /dev/tape /
170 To list files that will be excluded from the dump:
172 # xfsdump -e -v excluded_files=debug -f /dev/tape /
174 -z size
177 Specifies the maximum size, in kilobytes, of files to be included
178 in the dump. Files over this size, will be excluded from the
179 dump, except for DMF dual-state files when '-a option' is speci‐
180 fied (see '-a option' above). When specified, '-a option' takes
181 precedence over '-z option'. The size is an estimate based on the
182 number of disk blocks actually used by the file, and so does not
183 include holes. In other words, size refers to the amount of space
184 the file would take in the resulting dump. On an interactive
185 restore, the skipped file is visible with xfsrestore's 'ls' and
186 while you can use the 'add' and 'extract' commands, nothing will
187 be restored.
188 -A Do not dump extended file attributes. When dumping a filesystem
190 managed within a DMF environment this option should not be used.
191 DMF stores file migration status within extended attributes asso‐
192 ciated with each file. If these attributes are not preserved when
193 the filesystem is restored, files that had been in migrated state
194 will not be recallable by DMF. Note that dumps containing extended
195 file attributes cannot be restored with older versions of xfsre‐
196 store(8).
197 -B session_id
199 Specifies the ID of the dump session upon which this dump session
200 is to be based. If this option is specified, the -l (level) and
201 -R (resume) options are not allowed. Instead, xfsdump determines
202 if the current dump session should be incremental and/or resumed,
203 by looking at the base session's level and interrupted attributes.
204 If the base session was interrupted, the current dump session is a
205 resumption of that base at the same level. Otherwise, the current
206 dump session is an incremental dump with a level one greater than
207 that of the base session. This option allows incremental and
208 resumed dumps to be based on any previous dump, rather than just
209 the most recent.
210 -E Pre-erase media. If this option is specified, media is erased
212 prior to use. The operator is prompted for confirmation, unless
213 the -F option is also specified.
214 -F Don't prompt the operator. When xfsdump encounters a media object
216 containing non-xfsdump data, xfsdump normally asks the operator
217 for permission to overwrite. With this option the overwrite is
218 performed, no questions asked. When xfsdump encounters end-of-
219 media during a dump, xfsdump normally asks the operator if another
220 media object will be provided. With this option the dump is
221 instead interrupted.
222 -I Displays the xfsdump inventory (no dump is performed). xfsdump
224 records each dump session in an online inventory in /var/lib/xfs‐
225 dump/inventory. xfsdump uses this inventory to determine the base
226 for incremental dumps. It is also useful for manually identifying
227 a dump session to be restored. Suboptions to filter the inventory
228 display are described later.
229 -J Inhibits the normal update of the inventory. This is useful when
231 the media being dumped to will be discarded or overwritten.
232 -L session_label
234 Specifies a label for the dump session. It can be any arbitrary
235 string up to 255 characters long.
236 -M label [ -M label ... ]
238 Specifies a label for the first media object (for example, tape
239 cartridge) written on the corresponding destination during the
240 session. It can be any arbitrary string up to 255 characters
241 long. Multiple media object labels can be specified, one for each
242 destination.
243 -O options_file
245 Insert the options contained in options_file into the beginning of
246 the command line. The options are specified just as they would
247 appear if typed into the command line. In addition, newline char‐
248 acters (\n) can be used as whitespace. The options are placed
249 before all options actually given on the command line, just after
250 the command name. Only one -O option can be used. Recursive use
251 is ignored. The source filesystem cannot be specified in
252 options_file.
253 -R Resumes a previously interrupted dump session. If the most recent
255 dump at this dump's level (-l option) was interrupted, this dump
256 contains only files not in the interrupted dump and consistent
257 with the incremental level. However, files contained in the
258 interrupted dump that have been subsequently modified are re-
259 dumped.
260 -T Inhibits interactive dialogue timeouts. When the -F option is not
262 specified, xfsdump prompts the operator for labels and media
263 changes. Each dialogue normally times out if no response is sup‐
264 plied. This option prevents the timeout.
265 -Y length
267 Specify I/O buffer ring length. xfsdump uses a ring of output
268 buffers to achieve maximum throughput when dumping to tape drives.
269 The default ring length is 3. However, this is only supported
270 when running multi-threaded which has not been done for Linux yet
271 - making this option benign.
272 - A lone - causes the dump stream to be sent to the standard output,
274 where it can be piped to another utility such as xfsrestore(8) or
275 redirected to a file. This option cannot be used with the -f
276 option. The - must follow all other options and precede the
277 filesystem specification.
278 The filesystem, filesystem, can be specified either as a mount point or
280 as a special device file (for example, /dev/dsk/dks0d1s0). The
281 filesystem must be mounted to be dumped.
282
284 Dump Interruption
285 A dump can be interrupted at any time and later resumed. To interrupt,
286 type control-C (or the current terminal interrupt character). The
287 operator is prompted to select one of several operations, including
288 dump interruption. After the operator selects dump interruption, the
289 dump continues until a convenient break point is encountered (typically
290 the end of the current file). Very large files are broken into smaller
291 subfiles, so the wait for the end of the current file is brief.
292 Dump Resumption
294 A previously interrupted dump can be resumed by specifying the -R
295 option. If the most recent dump at the specified level was inter‐
296 rupted, the new dump does not include files already dumped, unless they
297 have changed since the interrupted dump.
298 Media Management
300 A single media object can contain many dump streams. Conversely, a
301 single dump stream can span multiple media objects. If a dump stream
302 is sent to a media object already containing one or more dumps, xfsdump
303 appends the new dump stream after the last dump stream. Media files
304 are never overwritten. If end-of-media is encountered during the
305 course of a dump, the operator is prompted to insert a new media object
306 into the drive. The dump stream continuation is appended after the
307 last media file on the new media object.
308 Inventory
310 Each dump session updates an inventory database in /var/lib/xfs‐
311 dump/inventory. xfsdump uses the inventory to determine the base of
312 incremental and resumed dumps.
313 This database can be displayed by invoking xfsdump with the -I option.
315 The display uses tabbed indentation to present the inventory hierarchi‐
316 cally. The first level is filesystem. The second level is session.
317 The third level is media stream (currently only one stream is sup‐
318 ported). The fourth level lists the media files sequentially composing
319 the stream.
320 The following suboptions are available to filter the display.
322 -I depth=n
324 (where n is 1, 2, or 3) limits the hierarchical depth of the dis‐
325 play. When n is 1, only the filesystem information from the inven‐
326 tory is displayed. When n is 2, only filesystem and session infor‐
327 mation are displayed. When n is 3, only filesystem, session and
328 stream information are displayed.
329 -I level=n
331 (where n is the dump level) limits the display to dumps of that
332 particular dump level.
333 The display may be restricted to media files contained in a specific
335 media object.
336 -I mobjid=value
338 (where value is a media ID) specifies the media object by its
339 media ID.
340 -I mobjlabel=value
342 (where value is a media label) specifies the media object by its
343 media label.
344 Similarly, the display can be restricted to a specific filesystem.
346 -I mnt=mount_point
348 (that is, [hostname:]pathname), identifies the filesystem by
349 mountpoint. Specifying the hostname is optional, but may be use‐
350 ful in a clustered environment where more than one host can be
351 responsible for dumping a filesystem.
352 -I fsid=filesystem_id
354 identifies the filesystem by filesystem ID.
355 -I dev=device_pathname
357 (that is, [hostname:]device_pathname) identifies the filesystem by
358 device. As with the mnt filter, specifying the hostname is
359 optional.
360 More than one of these suboptions, separated by commas, may be speci‐
362 fied at the same time to limit the display of the inventory to those
363 dumps of interest. However, at most four suboptions can be specified
364 at once: one to constrain the display hierarchy depth, one to constrain
365 the dump level, one to constrain the media object, and one to constrain
366 the filesystem.
367 For example, -I depth=1,mobjlabel="tape 1",mnt=host1:/test_mnt would
369 display only the filesystem information (depth=1) for those filesystems
370 that were mounted on host1:/test_mnt at the time of the dump, and only
371 those filesystems dumped to the media object labeled "tape 1".
372 Dump records may be removed (pruned) from the inventory using the xfs‐
374 invutil program.
375 An additional media file is placed at the end of each dump stream.
377 This media file contains the inventory information for the current dump
378 session. Its contents may be merged back into the online inventory
379 database at a later time using xfsrestore(1M).
380 The inventory files stored in /var/lib/xfsdump are not included in the
382 dump, even if that directory is contained within the filesystem being
383 dumped. Including the inventory in the dump may lead to loss or cor‐
384 ruption of data, should an older version be restored overwriting the
385 current version. To backup the xfsdump inventory, the contents of
386 /var/lib/xfsdump should be copied to another location which may then be
387 safely dumped. Upon restoration, those files may be copied back into
388 /var/lib/xfsdump, overwriting whatever files may be there, or xfsinvu‐
389 til(1M) may be used to selectively merge parts of the restored inven‐
390 tory back into the current inventory. Prior to version 1.1.8, xfsdump
391 would include the /var/lib/xfsdump directory in the dump. Care should
392 be taken not to overwrite the /var/lib/xfsdump directory when restoring
393 an old dump, by either restoring the filesystem to another location or
394 by copying the current contents of /var/lib/xfsdump to a safe place
395 prior to running xfsrestore(1M).
396 Labels
398 The operator can specify a label to identify the dump session and a
399 label to identify a media object. The session label is placed in every
400 media file produced in the course of the dump, and is recorded in the
401 inventory.
402 The media label is used to identify media objects, and is independent
404 of the session label. Each media file on the media object contains a
405 copy of the media label. An error is returned if the operator speci‐
406 fies a media label that does not match the media label on a media
407 object containing valid media files. Media labels are recorded in the
408 inventory.
409 UUIDs
411 UUIDs (Universally Unique Identifiers) are used in three places: to
412 identify the filesystem being dumped (using the filesystem UUID, see
413 xfs(5) for more details), to identify the dump session, and to identify
414 each media object. The inventory display (-I) includes all of these.
415 Dump Level Usage
417 The dump level mechanism provides a structured form of incremental
418 dumps. A dump of level level includes only files that have changed
419 since the most recent dump at a level less than level. For example,
420 the operator can establish a dump schedule that involves a full dump
421 every Friday and a daily incremental dump containing only files that
422 have changed since the previous dump. In this case Friday's dump would
423 be at level 0, Saturday's at level 1, Sunday's at level 2, and so on,
424 up to the Thursday dump at level 6.
425 The above schedule results in a very tedious restore procedure to fully
427 reconstruct the Thursday version of the filesystem; xfsrestore would
428 need to be fed all 7 dumps in sequence. A compromise schedule is to
429 use level 1 on Saturday, Monday, and Wednesday, and level 2 on Sunday,
430 Tuesday, and Thursday. The Monday and Wednesday dumps would take
431 longer, but the worst case restore requires the accumulation of just
432 three dumps, one each at level 0, level 1, and level 2.
433 Quotas
435 If the filesystem being dumped contains user quotas, xfsdump will use
436 xfs_quota(8) to store the quotas in a file called xfsdump_quotas in the
437 root of the filesystem to be dumped. This file will then be included in
438 the dump. Upon restoration, xfs_quota [4m(8) can be used to reactivate
439 the quotas for the filesystem. Note, however, that the xfsdump_quotas
440 file will probably require modification to change the filesystem or
441 UIDs if the filesystem has been restored to a different partition or
442 system. Group and project quotas will be handled in a similar fashion
443 and saved in files called xfsdump_quotas_group and xfsdump_quotas_proj
444 , respectively.
445 Excluding individual files
447 It may be desirable to exclude particular files or directories from the
448 dump. The -s option can be used to limit the dump to a specified
449 directory, and the -z option can be used to exclude files over a par‐
450 ticular size. Additionally, when xfsdump is run with the -e option,
451 files that are tagged with the "no dump" file attribute will not be
452 included in the dump. The chattr(1) command can be used to set this
453 attribute on individual files or entire subtrees.
454 To tag an individual file for exclusion from the dump:
456 $ chattr +d file
458 To tag all files in a subtree for exclusion from the dump:
460 $ chattr -R +d directory
462 Note that any new files or directories created in a directory which has
464 the "no dump" attribute set will automatically inherit this attribute.
465 Also note that xfsdump does not check directories for the "no dump"
466 attribute.
467 Care should be taken to note which files have been tagged. Under nor‐
469 mal operation, xfsdump will only report the number of files it will
470 skip. The -v excluded_files=debug option, however, will cause xfsdump
471 to list the inode numbers of the individual files affected.
472
474 To perform a level 0, single stream dump of the root filesystem to a
475 locally mounted tape drive, prompting for session and media labels when
476 required:
477 # xfsdump -f /dev/tape /
479 To specify session and media labels explicitly:
481 # xfsdump -L session_1 -M tape_0 -f /dev/tape /
483 To perform a dump to a remote tape using the minimal rmt protocol and a
485 set blocksize of 64k:
486 # xfsdump -m -b 65536 -f otherhost:/dev/tape /
488 To perform a level 0, multi-stream dump to two locally mounted tape
490 drives:
491 # xfsdump -L session_2 -f /dev/rmt/tps4d6v -M tape_1 \
493 -f /dev/rmt/tps5d6v -M tape_2 /
494 To perform a level 1 dump relative to the last level 0 dump recorded in
496 the inventory:
497 # xfsdump -l 1 -f /dev/tape /
499 To copy the contents of a filesystem to another directory (see xfsre‐
501 store(8)):
502 # xfsdump -J - / | xfsrestore -J - /new
504
507 /var/lib/xfsdump/inventory
508 dump inventory database
509
511 attr(1), rmt(8), xfsrestore(8), xfsinvutil(8), xfs_quota(8),
512 attr_get(2).
513
515 The exit code is 0 on normal completion, non-zero if an error occurs or
516 the dump is terminated by the operator.
517 For all verbosity levels greater than 0 (silent) the final line of the
519 output shows the exit status of the dump. It is of the form:
520 xfsdump: Dump Status: code
522 Where code takes one of the following values: SUCCESS (normal comple‐
524 tion), INTERRUPT (interrupted), QUIT (media no longer usable), INCOM‐
525 PLETE (dump incomplete), FAULT (software error), and ERROR (resource
526 error). Every attempt will be made to keep both the syntax and the
527 semantics of this log message unchanged in future versions of xfsdump.
528 However, it may be necessary to refine or expand the set of exit codes,
529 or their interpretation at some point in the future.
530 The message ``xfsdump: WARNING: unable to open directory: ino N:
532 Invalid argument'' can occur with filesystems which are actively being
533 modified while xfsdump is running. This can happen to either directory
534 or regular file inodes - affected files will not end up in the dump,
535 files below affected directories will be placed in the orphanage direc‐
536 tory by xfsrestore.
537
539 xfsdump does not dump unmounted filesystems.
540 The dump frequency field of /etc/fstab is not supported.
542 xfsdump uses the alert program only when a media change is required.
544 xfsdump requires root privilege (except for inventory display).
546 xfsdump can only dump XFS filesystems.
548 The media format used by xfsdump can only be understood by xfsrestore.
550 xfsdump does not know how to manage CD-ROM or other removable disk
552 drives.
553 xfsdump can become confused when doing incremental or resumed dumps if
555 on the same machine you dump two XFS filesystems and both filesystems
556 have the same filesystem identifier (UUID). Since xfsdump uses the
557 filesystem identifier to identify filesystems, xfsdump maintains one
558 combined set of dump inventories for both filesystems instead of two
559 sets of dump inventories. This scenario can happen only if dd or some
560 other block-by-block copy program was used to make a copy of an XFS
561 filesystem. See xfs_copy(8) and xfs(5) for more details.
562 xfsdump(8)