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.

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 xfsrestorehousekeeping directory. When performing a cumulative (-r option) restore, each successive invocation of xfsrestore 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.

-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 /

-w

This option is not normally recommended. This option will force xfsrestore to use small mmap regions which will reduce the likelihood of an mmap failure. However, this will slow down xfsrestore during directory processing when there are over 1 million inodes.

-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.

-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 only supported when running multi-threaded which has not been done for 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

Media Management

Inventory

Media Errors

Quotas

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), xfsrq(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.