xref: /freebsd/sbin/restore/restore.8 (revision e0c4386e7e71d93b0edc0c8fa156263fc4a8b0b6)
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28.Dd October 12, 2006
29.Dt RESTORE 8
30.Os
31.Sh NAME
32.Nm restore ,
33.Nm rrestore
34.Nd "restore files or file systems from backups made with dump"
35.Sh SYNOPSIS
36.Nm
37.Fl i
38.Op Fl dDhmNuvy
39.Op Fl b Ar blocksize
40.Op Fl f Ar file | Fl P Ar pipecommand
41.Op Fl s Ar fileno
42.Nm
43.Fl R
44.Op Fl dDNuvy
45.Op Fl b Ar blocksize
46.Op Fl f Ar file | Fl P Ar pipecommand
47.Op Fl s Ar fileno
48.Nm
49.Fl r
50.Op Fl dDNuvy
51.Op Fl b Ar blocksize
52.Op Fl f Ar file | Fl P Ar pipecommand
53.Op Fl s Ar fileno
54.Nm
55.Fl t
56.Op Fl dDhNuvy
57.Op Fl b Ar blocksize
58.Op Fl f Ar file | Fl P Ar pipecommand
59.Op Fl s Ar fileno
60.Op Ar
61.Nm
62.Fl x
63.Op Fl dDhmNuvy
64.Op Fl b Ar blocksize
65.Op Fl f Ar file | Fl P Ar pipecommand
66.Op Fl s Ar fileno
67.Op Ar
68.Sh DESCRIPTION
69The
70.Nm
71utility performs the inverse function of
72.Xr dump 8 .
73A full backup of a file system may be restored and
74subsequent incremental backups layered on top of it.
75Single files and
76directory subtrees may be restored from full or partial
77backups.
78The
79.Nm
80utility works across a network;
81to do this see the
82.Fl f
83and
84.Fl P
85flags described below.
86Other arguments to the command are file or directory
87names specifying the files that are to be restored.
88Unless the
89.Fl h
90flag is specified (see below),
91the appearance of a directory name refers to
92the files and (recursively) subdirectories of that directory.
93.Pp
94.Nm
95may also be invoked as
96.Nm rrestore .
97The
98.Bx 4.3
99option syntax is implemented for backward compatibility, but
100is not documented here.
101.Pp
102Exactly one of the following flags is required:
103.Bl -tag -width Ds
104.It Fl i
105This mode allows interactive restoration of files from a dump.
106After reading in the directory information from the dump,
107.Nm
108provides a shell like interface that allows the user to move
109around the directory tree selecting files to be extracted.
110The available commands are given below;
111for those commands that require an argument,
112the default is the current directory.
113.Bl -tag -width Fl
114.It Ic add Op Ar arg
115The current directory or specified argument is added to the list of
116files to be extracted.
117If a directory is specified, then it and all its descendents are
118added to the extraction list
119(unless the
120.Fl h
121flag is specified on the command line).
122Files that are on the extraction list are prepended with a ``*''
123when they are listed by
124.Ic ls .
125.It Ic \&cd Ar arg
126Change the current working directory to the specified argument.
127.It Ic delete Op Ar arg
128The current directory or specified argument is deleted from the list of
129files to be extracted.
130If a directory is specified, then it and all its descendents are
131deleted from the extraction list
132(unless the
133.Fl h
134flag is specified on the command line).
135The most expedient way to extract most of the files from a directory
136is to add the directory to the extraction list and then delete
137those files that are not needed.
138.It Ic extract
139All the files that are on the extraction list are extracted
140from the dump.
141The
142.Nm
143utility will ask which volume the user wishes to mount.
144The fastest way to extract a few files is to
145start with the last volume, and work towards the first volume.
146.It Ic help
147List a summary of the available commands.
148.It Ic \&ls Op Ar arg
149List the current or specified directory.
150Entries that are directories are appended with a ``/''.
151Entries that have been marked for extraction are prepended with a ``*''.
152If the verbose
153flag is set the inode number of each entry is also listed.
154.It Ic pwd
155Print the full pathname of the current working directory.
156.It Ic quit
157Exit immediately,
158even if the extraction list is not empty.
159.It Ic setmodes
160All the directories that have been added to the extraction list
161have their owner, modes, and times set;
162nothing is extracted from the dump.
163This is useful for cleaning up after a restore has been prematurely aborted.
164.It Ic verbose
165The sense of the
166.Fl v
167flag is toggled.
168When set, the verbose flag causes the
169.Ic ls
170command to list the inode numbers of all entries.
171It also causes
172.Nm
173to print out information about each file as it is extracted.
174.It Ic what
175Display dump header information, which includes: date,
176level, label, and the file system and host dump was made
177from.
178.El
179.It Fl R
180Request a particular tape of a multi volume set on which to restart
181a full restore
182(see the
183.Fl r
184flag below).
185This is useful if the restore has been interrupted.
186.It Fl r
187Restore (rebuild a file system).
188The target file system should be made pristine with
189.Xr newfs 8 ,
190mounted and the user
191.Xr cd 1 Ns 'd
192into the pristine file system
193before starting the restoration of the initial level 0 backup.
194If the
195level 0 restores successfully, the
196.Fl r
197flag may be used to restore
198any necessary incremental backups on top of the level 0.
199The
200.Fl r
201flag precludes an interactive file extraction and can be
202detrimental to one's health if not used carefully (not to mention
203the disk).
204An example:
205.Bd -literal -offset indent
206newfs /dev/da0s1a
207mount /dev/da0s1a /mnt
208cd /mnt
209
210restore rf /dev/sa0
211.Ed
212.Pp
213Note that
214.Nm
215leaves a file
216.Pa restoresymtable
217in the root directory to pass information between incremental
218restore passes.
219This file should be removed when the last incremental has been
220restored.
221.Pp
222The
223.Nm
224utility ,
225in conjunction with
226.Xr newfs 8
227and
228.Xr dump 8 ,
229may be used to modify file system parameters
230such as size or block size.
231.It Fl t
232The names of the specified files are listed if they occur
233on the backup.
234If no file argument is given,
235then the root directory is listed,
236which results in the entire content of the
237backup being listed,
238unless the
239.Fl h
240flag has been specified.
241Note that the
242.Fl t
243flag replaces the function of the old
244.Xr dumpdir 8
245program.
246.It Fl x
247The named files are read from the given media.
248If a named file matches a directory whose contents
249are on the backup
250and the
251.Fl h
252flag is not specified,
253the directory is recursively extracted.
254The owner, modification time,
255and mode are restored (if possible).
256If no file argument is given,
257then the root directory is extracted,
258which results in the entire content of the
259backup being extracted,
260unless the
261.Fl h
262flag has been specified.
263.El
264.Pp
265The following additional options may be specified:
266.Bl -tag -width Ds
267.It Fl b Ar blocksize
268The number of kilobytes per dump record.
269If the
270.Fl b
271option is not specified,
272.Nm
273tries to determine the media block size dynamically.
274.It Fl d
275Sends verbose debugging output to the standard error.
276.It Fl D
277This puts
278.Nm
279into degraded mode,
280causing restore to operate less efficiently
281but to try harder to read corrupted backups.
282.It Fl f Ar file
283Read the backup from
284.Ar file ;
285.Ar file
286may be a special device file
287like
288.Pa /dev/sa0
289(a tape drive),
290.Pa /dev/da1c
291(a disk drive),
292an ordinary file,
293or
294.Sq Fl
295(the standard input).
296If the name of the file is of the form
297.Dq host:file ,
298or
299.Dq user@host:file ,
300.Nm
301reads from the named file on the remote host using
302.Xr rmt 8 .
303.It Fl P Ar pipecommand
304Use
305.Xr popen 3
306to execute the
307.Xr sh 1
308script string defined by
309.Ar pipecommand
310as the input for every volume in the backup.
311This child pipeline's
312.Dv stdout
313.Pq Pa /dev/fd/1
314is redirected to the
315.Nm
316input stream, and the environment variable
317.Ev RESTORE_VOLUME
318is set to the current volume number being read.
319The
320.Ar pipecommand
321script is started each time a volume is loaded, as if it were a tape drive.
322.It Fl h
323Extract the actual directory,
324rather than the files that it references.
325This prevents hierarchical restoration of complete subtrees
326from the dump.
327.It Fl m
328Extract by inode numbers rather than by file name.
329This is useful if only a few files are being extracted,
330and one wants to avoid regenerating the complete pathname
331to the file.
332.It Fl N
333Do the extraction normally, but do not actually write any changes
334to disk.
335This can be used to check the integrity of dump media
336or other test purposes.
337.It Fl s Ar fileno
338Read from the specified
339.Ar fileno
340on a multi-file tape.
341File numbering starts at 1.
342.It Fl u
343When creating certain types of files, restore may generate a warning
344diagnostic if they already exist in the target directory.
345To prevent this, the
346.Fl u
347(unlink) flag causes restore to remove old entries before attempting
348to create new ones.
349This flag is recommended when using extended attributes
350to avoid improperly accumulating attributes on pre-existing files.
351.It Fl v
352Normally
353.Nm
354does its work silently.
355The
356.Fl v
357(verbose)
358flag causes it to type the name of each file it treats
359preceded by its file type.
360.It Fl y
361Do not ask the user whether to abort the restore in the event of an error.
362Always try to skip over the bad block(s) and continue.
363.El
364.Sh ENVIRONMENT
365.Bl -tag -width ".Ev TMPDIR"
366.It Ev TAPE
367Device from which to read backup.
368.It Ev TMPDIR
369Name of directory where temporary files are to be created.
370.El
371.Sh FILES
372.Bl -tag -width "./restoresymtable" -compact
373.It Pa /dev/sa0
374the default tape drive
375.It Pa /tmp/rstdir*
376file containing directories on the tape.
377.It Pa /tmp/rstmode*
378owner, mode, and time stamps for directories.
379.It Pa \&./restoresymtable
380information passed between incremental restores.
381.El
382.Sh DIAGNOSTICS
383The
384.Nm
385utility complains if it gets a read error.
386If
387.Fl y
388has been specified, or the user responds
389.Ql y ,
390.Nm
391will attempt to continue the restore.
392.Pp
393If a backup was made using more than one tape volume,
394.Nm
395will notify the user when it is time to mount the next volume.
396If the
397.Fl x
398or
399.Fl i
400flag has been specified,
401.Nm
402will also ask which volume the user wishes to mount.
403The fastest way to extract a few files is to
404start with the last volume, and work towards the first volume.
405.Pp
406There are numerous consistency checks that can be listed by
407.Nm .
408Most checks are self-explanatory or can ``never happen''.
409Common errors are given below.
410.Pp
411.Bl -tag -width Ds -compact
412.It <filename>: not found on tape
413The specified file name was listed in the tape directory,
414but was not found on the tape.
415This is caused by tape read errors while looking for the file,
416and from using a dump tape created on an active file system.
417.Pp
418.It expected next file <inumber>, got <inumber>
419A file that was not listed in the directory showed up.
420This can occur when using a dump created on an active file system.
421.Pp
422.It Incremental dump too low
423When doing incremental restore,
424a dump that was written before the previous incremental dump,
425or that has too low an incremental level has been loaded.
426.Pp
427.It Incremental dump too high
428When doing incremental restore,
429a dump that does not begin its coverage where the previous incremental
430dump left off,
431or that has too high an incremental level has been loaded.
432.Pp
433.It Tape read error while restoring <filename>
434.It Tape read error while skipping over inode <inumber>
435.It Tape read error while trying to resynchronize
436A tape (or other media) read error has occurred.
437If a file name is specified,
438then its contents are probably partially wrong.
439If an inode is being skipped or the tape is trying to resynchronize,
440then no extracted files have been corrupted,
441though files may not be found on the tape.
442.Pp
443.It resync restore, skipped <num> blocks
444After a dump read error,
445.Nm
446may have to resynchronize itself.
447This message lists the number of blocks that were skipped over.
448.El
449.Sh SEE ALSO
450.Xr dump 8 ,
451.Xr mount 8 ,
452.Xr newfs 8 ,
453.Xr rmt 8
454.Sh HISTORY
455The
456.Nm
457utility appeared in
458.Bx 4.2 .
459.Sh BUGS
460The
461.Nm
462utility can get confused when doing incremental restores from
463dumps that were made on active file systems without the
464.Fl L
465option (see
466.Xr dump 8 ) .
467.Pp
468A level zero dump must be done after a full restore.
469Because restore runs in user code,
470it has no control over inode allocation;
471thus a full dump must be done to get a new set of directories
472reflecting the new inode numbering,
473even though the contents of the files is unchanged.
474.Pp
475To do a network restore, you have to run restore as root.
476This is due
477to the previous security history of dump and restore.
478(restore is
479written to be setuid root, but we are not certain all bugs are gone
480from the restore code - run setuid at your own risk.)
481.Pp
482The temporary files
483.Pa /tmp/rstdir*
484and
485.Pa /tmp/rstmode*
486are generated with a unique name based on the date of the dump
487and the process ID (see
488.Xr mktemp 3 ) ,
489except for when
490.Fl r
491or
492.Fl R
493is used.
494Because
495.Fl R
496allows you to restart a
497.Fl r
498operation that may have been interrupted, the temporary files should
499be the same across different processes.
500In all other cases, the files are unique because it is possible to
501have two different dumps started at the same time, and separate
502operations should not conflict with each other.
503