Make the directory hashtable optional and controled via restore -H
[dump.git] / restore /
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28 .\" $Id:,v 1.33 2005/07/07 09:16:08 stelian Exp $
29 .\"
30 .TH RESTORE 8 "version __VERSION__ of __DATE__" BSD "System management commands"
32 restore \- restore files or file systems from backups made with dump
34 .B restore \-C
35 [\fB\-cdHklMvVy\fR]
36 [\fB\-b \fIblocksize\fR]
37 [\fB\-D \fIfilesystem\fR]
38 [\fB\-f \fIfile\fR]
39 [\fB\-F \fIscript\fR]
40 [\fB\-L \fIlimit\fR]
41 [\fB\-s \fIfileno\fR]
42 [\fB\-T \fIdirectory\fR]
43 .PP
44 .B restore \-i
45 [\fB\-acdhHklmMNouvVy\fR]
46 [\fB\-A \fIfile\fR]
47 [\fB\-b \fIblocksize\fR]
48 [\fB\-f \fIfile\fR]
49 [\fB\-F \fIscript\fR]
50 [\fB\-Q \fIfile\fR]
51 [\fB\-s \fIfileno\fR]
52 [\fB\-T \fIdirectory\fR]
53 .PP
54 .B restore \-P
55 .I file
56 [\fB\-acdhHklmMNuvVy\fR]
57 [\fB\-A \fIfile\fR]
58 [\fB\-b \fIblocksize\fR]
59 [\fB\-f \fIfile\fR]
60 [\fB\-F \fIscript\fR]
61 [\fB\-s \fIfileno\fR]
62 [\fB\-T \fIdirectory\fR]
63 [\fB\-X \fIfilelist\fR]
64 [ \fIfile ... \fR]
65 .PP
66 .B restore \-R
67 [\fB\-cdHklMNuvVy\fR]
68 [\fB\-b \fIblocksize\fR]
69 [\fB\-f \fIfile\fR]
70 [\fB\-F \fIscript\fR]
71 [\fB\-s \fIfileno\fR]
72 [\fB\-T \fIdirectory\fR]
73 .PP
74 .B restore \-r
75 [\fB\-cdHklMNuvVy\fR]
76 [\fB\-b \fIblocksize\fR]
77 [\fB\-f \fIfile\fR]
78 [\fB\-F \fIscript\fR]
79 [\fB\-s \fIfileno\fR]
80 [\fB\-T \fIdirectory\fR]
81 .PP
82 .B restore \-t
83 [\fB\-cdhHklMNuvVy\fR]
84 [\fB\-A \fIfile\fR]
85 [\fB\-b \fIblocksize\fR]
86 [\fB\-f \fIfile\fR]
87 [\fB\-F \fIscript\fR]
88 [\fB\-Q \fIfile\fR]
89 [\fB\-s \fIfileno\fR]
90 [\fB\-T \fIdirectory\fR]
91 [\fB\-X \fIfilelist\fR]
92 [ \fIfile ... \fR]
93 .PP
94 .B restore \-x
95 [\fB\-adchHklmMNouvVy\fR]
96 [\fB\-A \fIfile\fR]
97 [\fB\-b \fIblocksize\fR]
98 [\fB\-f \fIfile\fR]
99 [\fB\-F \fIscript\fR]
100 [\fB\-Q \fIfile\fR]
101 [\fB\-s \fIfileno\fR]
102 [\fB\-T \fIdirectory\fR]
103 [\fB\-X \fIfilelist\fR]
104 [ \fIfile ... \fR]
106 The
107 .B restore
108 command performs the inverse function of
109 .BR dump (8).
110 A full backup of a file system may be restored and subsequent incremental
111 backups layered on top of it. Single files and directory subtrees may be
112 restored from full or partial backups.
113 .B Restore
114 works across a network; to do this see the
115 .B \-f
116 flag described below. Other arguments to the command are file or directory
117 names specifying the files that are to be restored. Unless the
118 .B \-h
119 flag is specified (see below), the appearance of a directory name refers to
120 the files and (recursively) subdirectories of that directory.
121 .PP
122 Exactly one of the following flags is required:
123 .TP
124 .B \-C
125 This mode allows comparison of files from a dump.
126 .B Restore
127 reads the backup and compares its contents with files present on the disk. It
128 first changes its working directory to the root of the filesystem that was
129 dumped and compares the tape with the files in its new current directory. See
130 also the
131 .B \-L
132 flag described below.
133 .TP
134 .B \-i
135 This mode allows interactive restoration of files from a dump. After reading in
136 the directory information from the dump,
137 .B restore
138 provides a shell like interface that allows the user to move around the
139 directory tree selecting files to be extracted. The available commands are
140 given below; for those commands that require an argument, the default is the
141 current directory.
142 .RS
143 .TP
144 .B add \fR[\fIarg\fR]
145 The current directory or specified argument is added to the list of files to be
146 extracted. If a directory is specified, then it and all its descendents are
147 added to the extraction list (unless the
148 .B \-h
149 flag is specified on the command line). Files that are on the extraction list
150 are prepended with a \*(lq*\*(rq when they are listed by
151 .BR ls .
152 .TP
153 .BI cd " arg"
154 Change the current working directory to the specified argument.
155 .TP
156 .B delete \fR[\fIarg\fR]
157 The current directory or specified argument is deleted from the list of files
158 to be extracted. If a directory is specified, then it and all its descendents
159 are deleted from the extraction list (unless the
160 .B \-h
161 flag is specified on the command line). The most expedient way to extract most
162 of the files from a directory is to add the directory to the extraction list
163 and then delete those files that are not needed.
164 .TP
165 .B extract
166 All files on the extraction list are extracted from the dump.
167 .B Restore
168 will ask which volume the user wishes to mount. The fastest way to extract a f
169 ew files is to start with the last volume and work towards the first volume.
170 .TP
171 .B help
172 List a summary of the available commands.
173 .TP
174 .B ls \fR[\fIarg\fR]
175 List the current or specified directory. Entries that are directories are
176 appended with a \*(lq/\*(rq. Entries that have been marked for extraction are
177 prepended with a \*(lq*\*(rq. If the verbose flag is set, the inode number of
178 each entry is also listed.
179 .TP
180 .B pwd
181 Print the full pathname of the current working directory.
182 .TP
183 .B quit
184 .B Restore
185 immediately exits, even if the extraction list is not empty.
186 .TP
187 .B setmodes
188 All directories that have been added to the extraction list have their owner,
189 modes, and times set; nothing is extracted from the dump. This is useful for
190 cleaning up after a
191 .B restore
192 has been prematurely aborted.
193 .TP
194 .B verbose
195 The sense of the
196 .B \-v
197 flag is toggled. When set, the verbose flag causes the
198 .B ls
199 command to list the inode numbers of all entries. It also causes
200 .B restore
201 to print out information about each file as it is extracted.
202 .RE
203 .TP
204 .BI \-P " file"
205 .B Restore
206 creates a new Quick File Access file
207 .I file
208 from an existing dump file without restoring its contents.
209 .TP
210 .B \-R
211 .B Restore
212 requests a particular tape of a multi-volume set on which to restart a full
213 restore (see the
214 .B \-r
215 flag below). This is useful if the restore has been interrupted.
216 .TP
217 .B \-r
218 Restore (rebuild) a file system. The target file system should be made pristine
219 with
220 .BR mke2fs (8),
221 mounted, and the user
222 .BR cd 'd
223 into the pristine file system before starting the restoration of the initial
224 level 0 backup. If the level 0 restores successfully, the
225 .B \-r
226 flag may be used to restore any necessary incremental backups on top of the
227 level 0. The
228 .B \-r
229 flag precludes an interactive file extraction and can be detrimental to one's
230 health (not to mention the disk) if not used carefully. An example:
231 .IP
232 .RS 14
233 .B mke2fs /dev/sda1
234 .TP
235 .B mount /dev/sda1 /mnt
236 .TP
237 .B cd /mnt
238 .TP
239 .B restore rf /dev/st0
240 .RE
241 .IP
242 Note that
243 .B restore
244 leaves a file
245 .I restoresymtable
246 in the root directory to pass information between incremental restore passes.
247 This file should be removed when the last incremental has been restored.
248 .IP
249 .BR Restore ,
250 in conjunction with
251 .BR mke2fs (8)
252 and
253 .BR dump (8),
254 may be used to modify file system parameters such as size or block size.
255 .TP
256 .B \-t
257 The names of the specified files are listed if they occur on the backup. If no
258 file argument is given, the root directory is listed, which results in the
259 entire content of the backup being listed, unless the
260 .B \-h
261 flag has been specified. Note that the
262 .B \-t
263 flag replaces the function of the old
264 .BR dumpdir (8)
265 program. See also the
266 .B \-X
267 option below.
268 .TP
269 .B \-x
270 The named files are read from the given media. If a named file matches a
271 directory whose contents are on the backup and the
272 .B \-h
273 flag is not specified, the directory is recursively extracted. The owner,
274 modification time, and mode are restored (if possible). If no file argument is
275 given, the root directory is extracted, which results in the entire content of
276 the backup being extracted, unless the
277 .B \-h
278 flag has been specified. See also the
279 .B \-X
280 option below.
282 The following additional options may be specified:
283 .TP
284 .B \-a
285 In
286 .B \-i
287 or
288 .B \-x
289 mode,
290 .B restore
291 does ask the user for the volume number on which the files to be extracted are
292 supposed to be (in order to minimise the time by reading only the interesting
293 volumes). The
294 .B \-a
295 option disables this behaviour and reads all the volumes starting with 1. This
296 option is useful when the operator does not know on which volume the files to
297 be extracted are and/or when he prefers the longer unattended mode rather than
298 the shorter interactive mode.
299 .TP
300 .BI \-A " archive_file"
301 Read the table of contents from
302 .I archive_file
303 instead of the media. This option can be used in combination with the
304 .BR \-t ,
305 .BR \-i ,
306 or
307 .B \-x
308 options, making it possible to check whether files are on the media without
309 having to mount the media.
310 .TP
311 .BI \-b " blocksize"
312 The number of kilobytes per dump record. If the
313 .B \-b
314 option is not specified,
315 .B restore
316 tries to determine the media block size dynamically.
317 .TP
318 .B \-c
319 Normally,
320 .B restore
321 will try to determine dynamically whether the dump was made from an old
322 (pre-4.4) or new format file system. The
323 .B \-c
324 flag disables this check, and only allows reading a dump in the old format.
325 .TP
326 .B \-d
327 The
328 .B \-d
329 (debug) flag causes
330 .B restore
331 to print debug information.
332 .TP
333 .BI \-D " filesystem"
334 The
335 .B \-D
336 flag allows the user to specify the filesystem name when using
337 .B restore
338 with the
339 .B \-C
340 option to check the backup.
341 .TP
342 .BI \-f " file"
343 Read the backup from
344 .IR file ;
345 .I file
346 may be a special device file like
347 .I /dev/st0
348 (a tape drive),
349 .I /dev/sda1
350 (a disk drive), an ordinary file, or
351 .I \-
352 (the standard input). If the name of the file is of the form
353 .I host:file
354 or
355 .IR user@host:file ,
356 .B restore
357 reads from the named file on the remote host using
358 .BR rmt (8).
359 .TP
360 .BI \-F " script"
361 Run script at the beginning of each tape. The device name and the current
362 volume number are passed on the command line. The script must return 0 if
363 .B restore
364 should continue without asking the user to change the tape, 1 if
365 .B restore
366 should continue but ask the user to change the tape. Any other exit code will
367 cause
368 .B restore
369 to abort. For security reasons,
370 .B restore
371 reverts back to the real user ID and the real group ID before running the
372 script.
373 .TP
374 .B \-h
375 Extract the actual directory, rather than the files that it references. This
376 prevents hierarchical restoration of complete subtrees from the dump.
377 .TP
378 .BI \-H " hash_size"
379 Use a hashtable having the specified number of entries for storing the
380 directories entries instead of a linked list. This hashtable will
381 considerably speed up inode lookups (visible especialy in interactive
382 mode when adding/removing files from the restore list), but at the
383 price of much more memory usage. The default value is 1, meaning no
384 hashtable is used.
385 .TP
386 .B \-k
387 Use Kerberos authentication when contacting the remote tape server. (Only
388 available if this options was enabled when
389 .B restore
390 was compiled.)
391 .TP
392 .B \-l
393 When doing remote restores, assume the remote file is a regular file (instead
394 of a tape device). If you're restoring a remote compressed file, you will need
395 to specify this option or
396 .B restore
397 will fail to access it correctly.
398 .TP
399 .BI \-L " limit"
400 The
401 .B \-L
402 flag allows the user to specify a maximal number of miscompares when using
403 .B restore
404 with the
405 .B \-C
406 option to check the backup. If this limit is reached,
407 .B restore
408 will abort with an error message. A value of 0 (the default value) disables
409 the check.
410 .TP
411 .B \-m
412 Extract by inode numbers rather than by file name. This is useful if only a few
413 files are being extracted, and one wants to avoid regenerating the complete
414 pathname to the file.
415 .TP
416 .B \-M
417 Enables the multi-volume feature (for reading dumps made using the
418 .B \-M
419 option of dump). The name specified with
420 .B \-f
421 is treated as a prefix and
422 .B restore
423 tries to read in sequence from
424 .I <prefix>001, <prefix>002
425 etc.
426 .TP
427 .B \-N
428 The
429 .B \-N
430 flag causes
431 .B restore
432 to perform a full execution as requested by one of
433 .BR \-i ,
434 .BR \-R ,
435 .BR \-r ,
436 .B t
437 or
438 .B x
439 command without actually writing any file on disk.
440 .TP
441 .B \-o
442 The
443 .B \-o
444 flag causes
445 .B restore
446 to automatically restore the current directory permissions without asking the
447 operator whether to do so in one of
448 .B \-i
449 or
450 .B \-x
451 modes.
452 .TP
453 .BI \-Q " file"
454 Use the file
455 .I file
456 in order to read tape position as stored using the dump Quick File Access mode,
457 in one of
458 .BR \-i ,
459 .B \-x
460 or
461 .B \-t
462 mode.
463 .IP
464 It is recommended to set up the st driver to return logical tape positions
465 rather than physical before calling
466 .B dump/restore
467 with parameter
468 .BR \-Q .
469 Since not all tape devices support physical tape positions those tape devices
470 return an error during
471 .B dump/restore
472 when the st driver is set to the default physical setting. Please see the
473 .BR st (4)
474 man page, option
476 , or the
477 .BR mt(1)
478 man page, on how to set the driver to return logical tape positions.
479 .IP
480 Before calling
481 .B restore
482 with parameter
483 .BR \-Q ,
484 always make sure the st driver is set to return the same type of tape position
485 used during the call to
486 .BR dump .
487 Otherwise
488 .B restore
489 may be confused.
490 .IP
491 This option can be used when restoring from local or remote tapes (see above)
492 or from local or remote files.
493 .TP
494 .BI \-s " fileno"
495 Read from the specified
496 .I fileno
497 on a multi-file tape. File numbering starts at 1.
498 .TP
499 .BI \-T " directory"
500 The
501 .B \-T
502 flag allows the user to specify a directory to use for the storage of temporary
503 files. The default value is
504 .IR /tmp .
505 This flag is most useful when restoring files after having booted from a
506 floppy. There might be little or no space on the floppy filesystem, but another
507 source of space might exist.
508 .TP
509 .B \-u
510 When creating certain types of files,
511 .B restore
512 may generate a warning diagnostic if they already exist in the target
513 directory. To prevent this, the
514 .B \-u
515 (unlink) flag causes
516 .B restore
517 to remove old entries before attempting to create new ones.
518 .TP
519 .B \-v
520 Normally
521 .B restore
522 does its work silently. The
523 .B \-v
524 (verbose) flag causes it to type the name of each file it treats preceded by
525 its file type.
526 .TP
527 .B \-V
528 Enables reading multi-volume non-tape mediums like CDROMs.
529 .TP
530 .BI \-X " filelist"
531 Read list of files to be listed or extracted from the text file
532 .I filelist
533 in addition to those specified on the command line. This can be used in
534 conjunction with the
535 .B \-t
536 or
537 .B \-x
538 commands. The file
539 .I filelist
540 should contain file names separated by newlines.
541 .I filelist
542 may be an ordinary file or
543 .I -
544 (the standard input).
545 .TP
546 .B \-y
547 Do not ask the user whether to abort the restore in the event of an error.
548 Always try to skip over the bad block(s) and continue.
549 .PP
550 (The 4.3BSD option syntax is implemented for backward compatibility but is not
551 documented here.)
553 Complains if it gets a read error. If
554 .B y
555 has been specified, or the user responds
556 .BR y ,
557 .B restore
558 will attempt to continue the restore.
559 .PP
560 If a backup was made using more than one tape volume,
561 .B restore
562 will notify the user when it is time to mount the next volume. If the
563 .B \-x
564 or
565 .B \-i
566 flag has been specified,
567 .B restore
568 will also ask which volume the user wishes to mount. The fastest way to extract
569 a few files is to start with the last volume, and work towards the first volume.
570 .PP
571 There are numerous consistency checks that can be listed by
572 .BR restore .
573 Most checks are self-explanatory or can \*(lqnever happen\*(rq. Common errors
574 are given below:
575 .TP
576 .I Converting to new file system format
577 A dump tape created from the old file system has been loaded. It is
578 automatically converted to the new file system format.
579 .TP
580 .I <filename>: not found on tape
581 The specified file name was listed in the tape directory, but was not found on
582 the tape. This is caused by tape read errors while looking for the file, and
583 from using a dump tape created on an active file system.
584 .TP
585 .I expected next file <inumber>, got <inumber>
586 A file that was not listed in the directory showed up. This can occur when
587 using a dump created on an active file system.
588 .TP
589 .I Incremental dump too low
590 When doing an incremental restore, a dump that was written before the previous
591 incremental dump, or that has too low an incremental level has been loaded.
592 .TP
593 .I Incremental dump too high
594 When doing an incremental restore, a dump that does not begin its coverage
595 where the previous incremental dump left off, or that has too high an
596 incremental level has been loaded.
597 .TP
598 .I Tape read error while restoring <filename>
599 .TP
600 .I Tape read error while skipping over inode <inumber>
601 .TP
602 .I Tape read error while trying to resynchronize
603 A tape (or other media) read error has occurred. If a file name is specified,
604 its contents are probably partially wrong. If an inode is being skipped or the
605 tape is trying to resynchronize, no extracted files have been corrupted, though
606 files may not be found on the tape.
607 .TP
608 .I resync restore, skipped <num> blocks
609 After a dump read error,
610 .B restore
611 may have to resynchronize itself. This message lists the number of blocks that
612 were skipped over.
614 .B Restore
615 exits with zero status on success. Tape errors are indicated with an exit code
616 of 1.
617 .PP
618 When doing a comparison of files from a dump, an exit code of 2 indicates that
619 some files were modified or deleted since the dump was made.
621 If the following environment variable exists it will be utilized by
622 .BR restore :
623 .TP
624 .B TAPE
625 If no
626 .B \-f
627 option was specified,
628 .B restore
629 will use the device specified via
630 .B TAPE
631 as the dump device.
632 .B TAPE
633 may be of the form
634 .IR tapename ,
635 .I host:tapename
636 or
637 .IR user@host:tapename .
638 .TP
640 The directory given in
642 will be used instead of
643 .I /tmp
644 to store temporary files.
645 .TP
646 .B RMT
647 The environment variable
648 .B RMT
649 will be used to determine the pathname of the remote
650 .BR rmt (8)
651 program.
652 .TP
653 .B RSH
654 .B Restore
655 uses the contents of this variable to determine the name of the remote shell
656 command to use when doing a network restore (rsh, ssh etc.). If this variable
657 is not set,
658 .BR rcmd (3)
659 will be used, but only root will be able to do a network restore.
661 .TP
662 .I /dev/st0
663 the default tape drive
664 .TP
665 .I /tmp/rstdir*
666 file containing directories on the tape
667 .TP
668 .I /tmp/rstmode*
669 owner, mode, and time stamps for directories
670 .TP
671 .I ./restoresymtable
672 information passed between incremental restores
674 .BR dump (8),
675 .BR mount (8),
676 .BR mke2fs (8),
677 .BR rmt (8)
678 .SH BUGS
679 .B Restore
680 can get confused when doing incremental restores from dumps that were made on
681 active file systems.
682 .PP
683 A level 0 dump must be done after a full restore. Because
684 .B restore
685 runs in user code, it has no control over inode allocation; thus a full dump
686 must be done to get a new set of directories reflecting the new inode
687 numbering, even though the content of the files is unchanged.
688 .PP
689 The temporary files
690 .I /tmp/rstdir*
691 and
692 .I /tmp/rstmode*
693 are generated with a unique name based on the date of the dump and the process
694 ID (see
695 .BR mktemp (3) ),
696 except when
697 .B \-r
698 or
699 .B \-R
700 is used. Because
701 .B \-R
702 allows you to restart a
703 .B \-r
704 operation that may have been interrupted, the temporary files should be the
705 same across different processes. In all other cases, the files are unique
706 because it is possible to have two different dumps started at the same time,
707 and separate operations shouldn't conflict with each other.
708 .PP
709 To do a network restore, you have to run
710 .B restore
711 as root or use a remote shell replacement (see
712 .B RSH
713 variable). This is due to the previous security history of
714 .B dump
715 and
716 .BR restore .
717 (
718 .B restore
719 is written to be setuid root, but we are not certain all bugs are gone from the
720 code - run setuid at your own risk.)
721 .PP
722 At the end of restores in
723 .B \-i
724 or
725 .B \-x
726 modes (unless
727 .B \-o
728 option is in use),
729 .B restore
730 will ask the operator whether to set the permissions on the current
731 directory. If the operator confirms this action, the permissions
732 on the directory from where
733 .B restore
734 was launched will be replaced by the permissions on the dumped root
735 inode. Although this behaviour is not really a bug, it has proven itself
736 to be confusing for many users, so it is recommended to answer 'no',
737 unless you're performing a full restore and you do want to restore the
738 permissions on '/'.
739 .PP
740 It should be underlined that because it runs in user code,
741 .B restore
742 , when run with the
743 .B \-C
744 option, sees the files as the kernel presents them, whereas
745 .B dump
746 sees all the files on a given filesystem. In particular, this
747 can cause some confusion when comparing a dumped filesystem a part
748 of which is hidden by a filesystem mounted on top of it.
750 The
751 .B dump/restore
752 backup suite was ported to Linux's Second Extended File System by Remy Card
753 <card@Linux.EU.Org>. He maintained the initial versions of
754 .B dump
755 (up and including 0.4b4, released in january 1997).
756 .PP
757 Starting with 0.4b5, the new maintainer is Stelian Pop <>.
759 The
760 .B dump/restore
761 backup suite is available from <>
763 The
764 .B restore
765 command appeared in 4.2BSD.