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NAME | SYNOPSIS | DESCRIPTION | NOTES | EXAMPLES | FILES | SEE ALSO | DIAGNOSTICS | BUGS | COLOPHON |
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xfsrestore(8) System Manager's Manual xfsrestore(8)
xfsrestore - XFS filesystem incremental restore utility
xfsrestore -h
xfsrestore [ options ] -f source [ -f source ... ] dest
xfsrestore [ options ] - dest
xfsrestore -I [ subopt=value ... ]
xfsrestore restores filesystems from dumps produced by
xfsdump(8). Two modes of operation are available: simple and
cumulative.
The default is simple mode. xfsrestore populates the specified
destination directory, dest, with the files contained in the dump
media.
The -r option specifies the cumulative mode. Successive
invocations of xfsrestore are used to apply a chronologically
ordered sequence of delta dumps to a base (level 0) dump. The
contents of the filesystem at the time each dump was produced is
reproduced. This can involve adding, deleting, renaming,
linking, and unlinking files and directories.
A delta dump is defined as either an incremental dump (xfsdump -l
option with level > 0) or a resumed dump (xfsdump -R option).
The deltas must be applied in the order they were produced. Each
delta applied must have been produced with the previously applied
delta as its base.
xfsrestore keeps state information in the
xfsrestorehousekeepingdir, to inform subsequent invocations when
used in cumulative mode, or in the event a restore is
interrupted. To ensure that the state information can be
processed, a compatible version of xfsrestore must be used for
each subsequent invocation. Additionally, each invocation must
run on a system of the same endianness and page size.
The options to xfsrestore are:
-a housekeeping
Each invocation of xfsrestore creates a directory called
xfsrestorehousekeepingdir. This directory is normally
created directly under the dest directory. The -a option
allows the operator to specify an alternate directory,
housekeeping, in which xfsrestore creates the
xfsrestorehousekeepingdir directory. When performing a
cumulative (-r option) restore or resuming (-R option) a
restore, each successive invocation must specify the same
alternate directory.
-b blocksize
Specifies the blocksize, in bytes, to be used for the
restore. For other drives such as DAT or 8 mm , the same
blocksize used for the xfsdump operation must be specified
to restore the tape. The default block size is 1Mb.
-c progname
Use the specified program to alert the operator when a media
change is required. The alert program is typically a script
to send a mail or flash a window to draw the operator's
attention.
-e Prevents xfsrestore from overwriting existing files in the
dest directory.
-f source [ -f source ... ]
Specifies a source of the dump to be restored. This can be
the pathname of a device (such as a tape drive), a regular
file or a remote tape drive (see rmt(8)). This option must
be omitted if the standard input option (a lone - preceding
the dest specification) is specified.
-i Selects interactive operation. Once the on-media directory
hierarchy has been read, an interactive dialogue is begun.
The operator uses a small set of commands to peruse the
directory hierarchy, selecting files and subtrees for
extraction. The available commands are given below.
Initially nothing is selected, except for those subtrees
specified with -s command line options.
ls [arg]
List the entries in the current directory or the
specified directory, or the specified non-directory
file entry. Both the entry's original inode number
and name are displayed. Entries that are directories
are appended with a `/'. Entries that have been
selected for extraction are prepended with a `*'.
cd [arg]
Change the current working directory to the specified
argument, or to the filesystem root directory if no
argument is specified.
pwd Print the pathname of the current directory, relative
to the filesystem root.
add [arg]
The current directory or specified file or directory
within the current directory is selected for
extraction. If a directory is specified, then it and
all its descendents are selected. Entries that are
selected for extraction are prepended with a `*' when
they are listed by ls.
delete [arg]
The current directory or specified file or directory
within the current directory is deselected for
extraction. If a directory is specified, then it and
all its descendents are deselected. The most
expedient way to extract most of the files from a
directory is to select the directory and then
deselect those files that are not needed.
extract
Ends the interactive dialogue, and causes all
selected subtrees to be restored.
quit xfsrestore ends the interactive dialogue and
immediately exits, even if there are files or
subtrees selected for extraction.
help List a summary of the available commands.
-m Use the minimal tape protocol. This option cannot be used
without specifying a blocksize to be used (see -b option
above).
-n file
Allows xfsrestore to restore only files newer than file.
The modification time of file (i.e., as displayed with the
ls -l command) is compared to the inode modification time of
each file on the source media (i.e., as displayed with the
ls -lc command). A file is restored from media only if its
inode modification time is greater than or equal to the
modification time of file.
-o Restore file and directory owner/group even if not root.
When run with an effective user id of root, xfsrestore
restores owner and group of each file and directory. When
run with any other effective user id it does not, unless
this option is specified.
-p interval
Causes progress reports to be printed at intervals of
interval seconds. The interval value is approximate,
xfsrestore will delay progress reports to avoid undue
processing overhead.
-q Source tape drive is a QIC tape. QIC tapes only use a 512
byte blocksize, for which xfsrestore must make special
allowances.
-r Selects the cumulative mode of operation. The -a and
destination options must be the same for each invocation.
-s subtree
Specifies a subtree to restore. Any number of -s options
are allowed. The restore is constrained to the union of all
subtrees specified. Each subtree is specified as a pathname
relative to the restore dest. If a directory is specified,
the directory and all files beneath that directory are
restored.
-t Displays the contents of the dump, but does not create or
modify any files or directories. It may be desirable to set
the verbosity level to silent when using this option.
-v verbosity
-v subsys=verbosity[,subsys=verbosity,...]
Specifies the level of detail used for messages displayed
during the course of the restore. The verbosity argument can
be passed as either a string or an integer. If passed as a
string the following values may be used: silent, verbose,
trace, debug, or nitty. If passed as an integer, values
from 0-5 may be used. The values 0-4 correspond to the
strings already listed. The value 5 can be used to produce
even more verbose debug output.
The first form of this option activates message logging
across all restore subsystems. The second form allows the
message logging level to be controlled on a per-subsystem
basis. The two forms can be combined (see the example
below). The argument subsys can take one of the following
values: general, proc, drive, media, inventory, and tree.
For example, to restore the root filesystem with tracing
activated for all subsystems:
# xfsrestore -v trace -f /dev/tape /
To enable debug-level tracing for drive and media
operations:
# xfsrestore -v drive=debug,media=debug -f /dev/tape /
To enable tracing for all subsystems, and debug level
tracing for drive operations only:
# xfsrestore -v trace,drive=debug -f /dev/tape /
-A Do not restore extended file attributes. When restoring a
filesystem managed within a DMF environment this option
should not be used. DMF stores file migration status within
extended attributes associated with each file. If these
attributes are not preserved when the filesystem is
restored, files that had been in migrated state will not be
recallable by DMF. Note that dumping of extended file
attributes is also optional.
-B Change the ownership and permissions of the destination
directory to match those of the root directory of the dump.
-D Restore DMAPI (Data Management Application Programming
Interface) event settings. If the restored filesystem will
be managed within the same DMF environment as the original
dump it is essential that the -D option be used. Otherwise
it is not usually desirable to restore these settings.
-E Prevents xfsrestore from overwriting newer versions of
files. The inode modification time of the on-media file is
compared to the inode modification time of corresponding
file in the dest directory. The file is restored only if
the on-media version is newer than the version in the dest
directory. The inode modification time of a file can be
displayed with the ls -lc command.
-F Inhibit interactive operator prompts. This option inhibits
xfsrestore from prompting the operator for verification of
the selected dump as the restore target and from prompting
for any media change.
-I Causes the xfsdump inventory to be displayed (no restore is
performed). Each time xfsdump is used, an online inventory
in /var/lib/xfsdump/inventory is updated. This is used to
determine the base for incremental dumps. It is also useful
for manually identifying a dump session to be restored (see
the -L and -S options). Suboptions to filter the inventory
display are described later.
-J Inhibits inventory update when on-media session inventory
encountered during restore. xfsrestore opportunistically
updates the online inventory when it encounters an on-media
session inventory, but only if run with an effective user id
of root and only if this option is not given.
-K Force xfsrestore to use dump format 2 generation numbers.
Normally the need for this is determined automatically, but
this option is required on the first xfsrestore invocation
in the rare case that a cumulative restore begins with a
format 3 (or newer) dump and will be followed by a format 2
dump.
-L session_label
Specifies the label of the dump session to be restored. The
source media is searched for this label. It is any
arbitrary string up to 255 characters long. The label of
the desired dump session can be copied from the inventory
display produced by the -I option.
-O options_file
Insert the options contained in options_file into the
beginning of the command line. The options are specified
just as they would appear if typed into the command line.
In addition, newline characters (\n) can be used as
whitespace. The options are placed before all options
actually given on the command line, just after the command
name. Only one -O option can be used. Recursive use is
ignored. The destination directory cannot be specified in
options_file.
-Q Force completion of an interrupted restore session. This
option is required to work around one specific pathological
scenario. When restoring a dump session which was
interrupted due to an EOM condition and no online session
inventory is available, xfsrestore cannot know when the
restore of that dump session is complete. The operator is
forced to interrupt the restore session. In that case, if
the operator tries to subsequently apply a resumed dump
(using the -r option), xfsrestore refuses to do so. The
operator must tell xfsrestore to consider the base restore
complete by using this option when applying the resumed
dump.
-R Resume a previously interrupted restore. xfsrestore can be
interrupted at any time by pressing the terminal interrupt
character (see stty(1)). Use this option to resume the
restore. The -a and destination options must be the same.
-S session_id
Specifies the session UUID of the dump session to be
restored. The source media is searched for this UUID. The
UUID of the desired dump session can be copied from the
inventory display produced by the -I option.
-T Inhibits interactive dialogue timeouts. xfsrestore prompts
the operator for media changes. This dialogue normally
times out if no response is supplied. This option prevents
the timeout.
-X subtree
Specifies a subtree to exclude. This is the converse of the
-s option. Any number of -X options are allowed. Each
subtree is specified as a pathname relative to the restore
dest. If a directory is specified, the directory and all
files beneath that directory are excluded.
-Y io_ring_length
Specify I/O buffer ring length. xfsrestore uses a ring of
input buffers to achieve maximum throughput when restoring
from tape drives. The default ring length is 3. However,
this is not currently enabled on Linux yet, making this
option benign.
- A lone - causes the standard input to be read as the source
of the dump to be restored. Standard input can be a pipe
from another utility (such as xfsdump(8)) or a redirected
file. This option cannot be used with the -f option. The -
must follow all other options, and precede the dest
specification.
The dumped filesystem is restored into the dest directory. There
is no default; the dest must be specified.
Cumulative Restoration
A base (level 0) dump and an ordered set of delta dumps can be
sequentially restored, each on top of the previous, to reproduce
the contents of the original filesystem at the time the last
delta was produced. The operator invokes xfsrestore once for
each dump. The -r option must be specified. The dest directory
must be the same for all invocations. Each invocation leaves a
directory named xfsrestorehousekeeping in the dest directory
(however, see the -a option above). This directory contains the
state information that must be communicated between invocations.
The operator must remove this directory after the last delta has
been applied.
xfsrestore also generates a directory named orphanage in the dest
directory. xfsrestore removes this directory after completing a
simple restore. However, if orphanage is not empty, it is not
removed. This can happen if files present on the dump media are
not referenced by any of the restored directories. The orphanage
has an entry for each such file. The entry name is the file's
original inode number, a ".", and the file's generation count
modulo 4096 (only the lower 12 bits of the generation count are
used).
xfsrestore does not remove the orphanage after cumulative
restores. Like the xfsrestorehousekeeping directory, the
operator must remove it after applying all delta dumps.
Media Management
A dump consists of one or more media files contained on one or
more media objects. A media file contains all or a portion of
the filesystem dump. Large filesystems are broken up into
multiple media files to minimize the impact of media dropouts,
and to accommodate media object boundaries (end-of-media).
A media object is any storage medium: a tape cartridge, a remote
tape device (see rmt(8)), a regular file, or the standard input
(currently other removable media drives are not supported). Tape
cartridges can contain multiple media files, which are typically
separated by (in tape parlance) file marks. If a dump spans
multiple media objects, the restore must begin with the media
object containing the first media file dumped. The operator is
prompted when the next media object is needed.
Media objects can contain more than one dump. The operator can
select the desired dump by specifying the dump label (-L option),
or by specifying the dump UUID (-S option). If neither is
specified, xfsrestore scans the entire media object, prompting
the operator as each dump session is encountered.
The inventory display (-I option) is useful for identifying the
media objects required. It is also useful for identifying a dump
session. The session UUID can be copied from the inventory
display to the -S option argument to unambiguously identify a
dump session to be restored.
Dumps placed in regular files or the standard output do not span
multiple media objects, nor do they contain multiple dumps.
Inventory
Each dump session updates an inventory database in
/var/lib/xfsdump/inventory. This database can be displayed by
invoking xfsrestore with the -I option. The display uses tabbed
indentation to present the inventory hierarchically. The first
level is filesystem. The second level is session. The third
level is media stream (currently only one stream is supported).
The fourth level lists the media files sequentially composing the
stream.
The following suboptions are available to filter the display.
-I depth=n
(where n is 1, 2, or 3) limits the hierarchical depth of the
display. When n is 1, only the filesystem information from
the inventory is displayed. When n is 2, only filesystem and
session information are displayed. When n is 3, only
filesystem, session and stream information are displayed.
-I level=n
(where n is the dump level) limits the display to dumps of
that particular dump level.
The display may be restricted to media files contained in a
specific media object.
-I mobjid=value
(where value is a media ID) specifies the media object by
its media ID.
-I mobjlabel=value
(where value is a media label) specifies the media object by
its media label.
Similarly, the display can be restricted to a specific
filesystem.
-I mnt=mount_point
(that is, [hostname:]pathname), identifies the filesystem by
mountpoint. Specifying the hostname is optional, but may be
useful in a clustered environment where more than one host
can be responsible for dumping a filesystem.
-I fsid=filesystem_id
identifies the filesystem by filesystem ID.
-I dev=device_pathname
(that is, [hostname:]device_pathname) identifies the
filesystem by device. As with the mnt filter, specifying
the hostname is optional.
More than one of these suboptions, separated by commas, may be
specified at the same time to limit the display of the inventory
to those dumps of interest. However, at most four suboptions can
be specified at once: one to constrain the display hierarchy
depth, one to constrain the dump level, one to constrain the
media object, and one to constrain the filesystem.
For example, -I depth=1,mobjlabel="tape 1",mnt=host1:/test_mnt
would display only the filesystem information (depth=1) for those
filesystems that were mounted on host1:/test_mnt at the time of
the dump, and only those filesystems dumped to the media object
labeled "tape 1".
Dump records may be removed (pruned) from the inventory using the
xfsinvutil program.
An additional media file is placed at the end of each dump
stream. This media file contains the inventory information for
the current dump session. If the online inventory files in
/var/lib/xfsdump/inventory are missing information for the
current dump session, then the inventory information in the media
file is automatically added to the files in
/var/lib/xfsdump/inventory. If you wish to incorporate the
inventory information from the media file without restoring any
data, you may do so using the -t option:
# xfsrestore -t -f /dev/tape
This is useful to rebuild the inventory database if it is ever
lost or corrupted. The only caveat is that xfsrestore needs to
read through the entire dump in order to reach the inventory
media file. This could become time consuming for dump sessions
with large media files.
Media Errors
xfsdump is tolerant of media errors, but cannot do error
correction. If a media error occurs in the body of a media file,
the filesystem file represented at that point is lost. The bad
portion of the media is skipped, and the restoration resumes at
the next filesystem file after the bad portion of the media.
If a media error occurs in the beginning of the media file, the
entire media file is lost. For this reason, large dumps are
broken into a number of reasonably sized media files. The
restore resumes with the next media file.
Quotas
When xfsdump dumps a filesystem with user quotas, it creates a
file in the root of the dump called xfsdump_quotas. xfsrestore
can restore this file like any other file included in the dump.
This file can be processed by the restore command of xfs_quota(8)
to reactivate the quotas. However, the xfsdump_quotas file
contains information which may first require modification;
specifically the filesystem name and the user ids. If you are
restoring the quotas for the same users on the same filesystem
from which the dump was taken, then no modification will be
necessary. However, if you are restoring the dump to a different
filesystem, you will need to:
- ensure the new filesystem is mounted with the quota option
- modify the xfsdump_quotas file to contain the new filesystem
name
- ensure the uids in the xfsdump_quotas file are correct
Once the quota information has been verified, the restore command
of xfs_quota(8) can be used to apply the quota limits to the
filesystem.
Group and project quotas are handled in a similar fashion and
will be restored in files called xfsdump_quotas_group and
xfsdump_quotas_proj, respectively.
To restore the root filesystem from a locally mounted tape:
# xfsrestore -f /dev/tape /
To restore from a remote tape, specifying the dump session id:
# xfsrestore -L session_1 -f otherhost:/dev/tape /new
To restore the contents a of a dump to another subdirectory:
# xfsrestore -f /dev/tape /newdir
To copy the contents of a filesystem to another directory (see
xfsdump(8)):
# xfsdump -J - / | xfsrestore -J - /new
/var/lib/xfsdump/inventory
dump inventory database
rmt(8), xfsdump(8), xfsinvutil(8), xfs_quota(8), attr_set(2).
The exit code is 0 on normal completion, and non-zero if an error
occurred or the restore was terminated by the operator.
For all verbosity levels greater than 0 (silent) the final line
of the output shows the exit status of the restore. It is of the
form:
xfsdump: Restore Status: code
Where code takes one of the following values: SUCCESS (normal
completion), INTERRUPT (interrupted), QUIT (media no longer
usable), INCOMPLETE (restore incomplete), FAULT (software error),
and ERROR (resource error). Every attempt will be made to keep
both the syntax and the semantics of this log message unchanged
in future versions of xfsrestore. However, it may be necessary
to refine or expand the set of exit codes, or their
interpretation at some point in the future.
Pathnames of restored non-directory files (relative to the dest
directory) must be 1023 characters (MAXPATHLEN) or less. Longer
pathnames are discarded and a warning message displayed.
There is no verify option to xfsrestore. This would allow the
operator to compare a filesystem dump to an existing filesystem,
without actually doing a restore.
The interactive commands (-i option) do not understand regular
expressions.
When the minimal rmt option is specified, xfsrestore applies it
to all remote tape sources. The same blocksize (specified by the
-b option) is used for all these remote drives.
xfsrestore uses the alert program only when a media change is
required.
Cumulative mode (-r option) requires that the operator invoke
xfsrestore for the base and for each delta to be applied in
sequence to the base. It would be better to allow the operator
to identify the last delta in the sequence of interest, and let
xfsrestore work backwards from that delta to identify and apply
the preceding deltas and base dump, all in one invocation.
This page is part of the xfsdump (XFS dump and restore) project.
Information about the project can be found at ⟨http://xfs.org/⟩.
If you have a bug report for this manual page, send it to
[email protected]. This page was obtained from the
project's upstream Git repository
⟨https://git.kernel.org/pub/scm/fs/xfs/xfsprogs-dev.git⟩ on
2024-06-14. (At that time, the date of the most recent commit
that was found in the repository was 2022-12-15.) If you
discover any rendering problems in this HTML version of the page,
or you believe there is a better or more up-to-date source for
the page, or you have corrections or improvements to the
information in this COLOPHON (which is not part of the original
manual page), send a mail to [email protected]
xfsrestore(8)
Pages that refer to this page: xfs(5), xfs_copy(8), xfsdump(8), xfsinvutil(8)
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HTML rendering created 2024-06-26 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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