NAME¶
restore - restore files or file systems from backups made with dump
SYNOPSIS¶
restore -C [
-cdHklMvVy] [
-b blocksize] [
-D
filesystem] [
-f file] [
-F script] [
-L limit] [
-s fileno] [
-T
directory]
restore -i [
-acdhHklmMNouvVy] [
-A file] [
-b
blocksize] [
-f file] [
-F script] [
-Q file] [
-s fileno] [
-T
directory]
restore -P file [
-acdhHklmMNuvVy] [
-b
blocksize] [
-f file] [
-F script] [
-s fileno] [
-T directory] [
-X
filelist] [
file ... ]
restore -R [
-cdHklMNuvVy] [
-b blocksize] [
-f
file] [
-F script] [
-s fileno] [
-T directory]
restore -r [
-cdHklMNuvVy] [
-b blocksize] [
-f
file] [
-F script] [
-s fileno] [
-T directory]
restore -t [
-cdhHklMNuvVy] [
-A file] [
-b
blocksize] [
-f file] [
-F script] [
-Q file] [
-s fileno] [
-T
directory] [
-X filelist] [
file ... ]
restore -x [
-adchHklmMNouvVy] [
-A file] [
-b
blocksize] [
-f file] [
-F script] [
-Q file] [
-s fileno] [
-T
directory] [
-X filelist] [
file ... ]
DESCRIPTION¶
The
restore command performs the inverse function of
dump(8). A
full backup of a file system may be restored and subsequent incremental
backups layered on top of it. Single files and directory subtrees may be
restored from full or partial backups.
Restore works across a network;
to do this see the
-f flag described below. Other arguments to the
command are file or directory names specifying the files that are to be
restored. Unless the
-h flag is specified (see below), the appearance
of a directory name refers to the files and (recursively) subdirectories of
that directory.
Exactly one of the following flags is required:
- -C
- This mode allows comparison of files from a dump.
Restore reads the backup and compares its contents with files
present on the disk. It first changes its working directory to the root of
the filesystem that was dumped and compares the tape with the files in its
new current directory. See also the -L flag described below.
- -i
- This mode allows interactive restoration of files from a
dump. After reading in the directory information from the dump,
restore provides a shell like interface that allows the user to
move around the directory tree selecting files to be extracted. The
available commands are given below; for those commands that require an
argument, the default is the current directory.
- add [arg]
- The current directory or specified argument is added to the
list of files to be extracted. If a directory is specified, then it and
all its descendents are added to the extraction list (unless the -h
flag is specified on the command line). Files that are on the extraction
list are prepended with a “*” when they are listed by
ls.
- cd arg
- Change the current working directory to the specified
argument.
- delete [arg]
- The current directory or specified argument is deleted from
the list of files to be extracted. If a directory is specified, then it
and all its descendents are deleted from the extraction list (unless the
-h flag is specified on the command line). The most expedient way
to extract most of the files from a directory is to add the directory to
the extraction list and then delete those files that are not needed.
- extract
- All files on the extraction list are extracted from the
dump. Restore will ask which volume the user wishes to mount. The
fastest way to extract a f ew files is to start with the last volume and
work towards the first volume.
- help
- List a summary of the available commands.
- ls [arg]
- List the current or specified directory. Entries that are
directories are appended with a “/”. Entries that have been
marked for extraction are prepended with a “*”. If the verbose
flag is set, the inode number of each entry is also listed.
- pwd
- Print the full pathname of the current working
directory.
- quit
- Restore immediately exits, even if the extraction
list is not empty.
- setmodes
- All directories that have been added to the extraction list
have their owner, modes, and times set; nothing is extracted from the
dump. This is useful for cleaning up after a restore has been
prematurely aborted.
- verbose
- The sense of the -v flag is toggled. When set, the
verbose flag causes the ls command to list the inode numbers of all
entries. It also causes restore to print out information about each
file as it is extracted.
- -P file
- Restore creates a new Quick File Access file
file from an existing dump file without restoring its
contents.
- -R
- Restore requests a particular tape of a multi-volume
set on which to restart a full restore (see the -r flag below).
This is useful if the restore has been interrupted.
- -r
- Restore (rebuild) a file system. The target file system
should be made pristine with mke2fs(8), mounted, and the user
cd'd into the pristine file system before starting the restoration
of the initial level 0 backup. If the level 0 restores successfully, the
-r flag may be used to restore any necessary incremental backups on
top of the level 0. The -r flag precludes an interactive file
extraction and can be detrimental to one's health (not to mention the
disk) if not used carefully. An example:
mke2fs /dev/sda1
- mount /dev/sda1 /mnt
- cd /mnt
- restore rf /dev/st0
- Note that restore leaves a file
restoresymtable in the root directory to pass information between
incremental restore passes. This file should be removed when the last
incremental has been restored.
- Restore, in conjunction with mke2fs(8) and
dump(8), may be used to modify file system parameters such as size
or block size.
- -t
- The names of the specified files are listed if they occur
on the backup. If no file argument is given, the root directory is listed,
which results in the entire content of the backup being listed, unless the
-h flag has been specified. Note that the -t flag replaces
the function of the old dumpdir(8) program. See also the -X
option below.
- -x
- The named files are read from the given media. If a named
file matches a directory whose contents are on the backup and the
-h flag is not specified, the directory is recursively extracted.
The owner, modification time, and mode are restored (if possible). If no
file argument is given, the root directory is extracted, which results in
the entire content of the backup being extracted, unless the -h
flag has been specified. See also the -X option below.
OPTIONS¶
The following additional options may be specified:
- -a
- In -i or -x mode, restore does ask the
user for the volume number on which the files to be extracted are supposed
to be (in order to minimise the time by reading only the interesting
volumes). The -a option disables this behaviour and reads all the
volumes starting with 1. This option is useful when the operator does not
know on which volume the files to be extracted are and/or when he prefers
the longer unattended mode rather than the shorter interactive mode.
- -A archive_file
- Read the table of contents from archive_file instead
of the media. This option can be used in combination with the -t,
-i, or -x options, making it possible to check whether files
are on the media without having to mount the media.
- -b blocksize
- The number of kilobytes per dump record. If the -b
option is not specified, restore tries to determine the media block
size dynamically.
- -c
- Normally, restore will try to determine dynamically
whether the dump was made from an old (pre-4.4) or new format file system.
The -c flag disables this check, and only allows reading a dump in
the old format.
- -d
- The -d (debug) flag causes restore to print
debug information.
- -D filesystem
- The -D flag allows the user to specify the
filesystem name when using restore with the -C option to
check the backup.
- -f file
- Read the backup from file; file may be a
special device file like /dev/st0 (a tape drive), /dev/sda1
(a disk drive), an ordinary file, or - (the standard input). If the
name of the file is of the form host:file or user@host:file,
restore reads from the named file on the remote host using
rmt(8).
- -F script
- Run script at the beginning of each tape. The device name
and the current volume number are passed on the command line. The script
must return 0 if restore should continue without asking the user to
change the tape, 1 if restore should continue but ask the user to
change the tape. Any other exit code will cause restore to abort.
For security reasons, restore reverts back to the real user ID and
the real group ID before running the script.
- -h
- Extract the actual directory, rather than the files that it
references. This prevents hierarchical restoration of complete subtrees
from the dump.
- -H hash_size
- Use a hashtable having the specified number of entries for
storing the directories entries instead of a linked list. This hashtable
will considerably speed up inode lookups (visible especially in
interactive mode when adding/removing files from the restore list), but at
the price of much more memory usage. The default value is 1, meaning no
hashtable is used.
- -k
- Use Kerberos authentication when contacting the remote tape
server. (Only available if this options was enabled when restore
was compiled.)
- -l
- When doing remote restores, assume the remote file is a
regular file (instead of a tape device). If you're restoring a remote
compressed file, you will need to specify this option or restore
will fail to access it correctly.
- -L limit
- The -L flag allows the user to specify a maximal
number of miscompares when using restore with the -C option
to check the backup. If this limit is reached, restore will abort
with an error message. A value of 0 (the default value) disables the
check.
- -m
- Extract by inode numbers rather than by file name. This is
useful if only a few files are being extracted, and one wants to avoid
regenerating the complete pathname to the file.
- -M
- Enables the multi-volume feature (for reading dumps made
using the -M option of dump). The name specified with -f is
treated as a prefix and restore tries to read in sequence from
<prefix>001, <prefix>002 etc.
- -N
- The -N flag causes restore to perform a full
execution as requested by one of -i, -R, -r, t
or x command without actually writing any file on disk.
- -o
- The -o flag causes restore to automatically
restore the current directory permissions without asking the operator
whether to do so in one of -i or -x modes.
- -Q file
- Use the file file in order to read tape position as
stored using the dump Quick File Access mode, in one of -i,
-x or -t mode.
- It is recommended to set up the st driver to return logical
tape positions rather than physical before calling dump/restore
with parameter -Q. Since not all tape devices support physical tape
positions those tape devices return an error during dump/restore
when the st driver is set to the default physical setting. Please see the
st(4) man page, option MTSETDRVBUFFER , or the mt(1)
man page, on how to set the driver to return logical tape positions.
- Before calling restore with parameter -Q,
always make sure the st driver is set to return the same type of tape
position used during the call to dump. Otherwise restore may
be confused.
- This option can be used when restoring from local or remote
tapes (see above) or from local or remote files.
- -s fileno
- Read from the specified fileno on a multi-file tape.
File numbering starts at 1.
- -T directory
- The -T flag allows the user to specify a directory
to use for the storage of temporary files. The default value is
/tmp. This flag is most useful when restoring files after having
booted from a floppy. There might be little or no space on the floppy
filesystem, but another source of space might exist.
- -u
- When creating certain types of files, restore may
generate a warning diagnostic if they already exist in the target
directory. To prevent this, the -u (unlink) flag causes
restore to remove old entries before attempting to create new
ones.
- -v
- Normally restore does its work silently. The
-v (verbose) flag causes it to type the name of each file it treats
preceded by its file type.
- -V
- Enables reading multi-volume non-tape mediums like
CDROMs.
- -X filelist
- Read list of files to be listed or extracted from the text
file filelist in addition to those specified on the command line.
This can be used in conjunction with the -t or -x commands.
The file filelist should contain file names separated by newlines.
filelist may be an ordinary file or - (the standard
input).
- -y
- Do not ask the user whether to abort the restore in the
event of an error. Always try to skip over the bad block(s) and
continue.
(The 4.3BSD option syntax is implemented for backward compatibility but is not
documented here.)
DIAGNOSTICS¶
Complains if it gets a read error. If
y has been specified, or the user
responds
y,
restore will attempt to continue the restore.
If a backup was made using more than one tape volume,
restore will notify
the user when it is time to mount the next volume. If the
-x or
-i flag has been specified,
restore will also ask which volume
the user wishes to mount. The fastest way to extract a few files is to start
with the last volume, and work towards the first volume.
There are numerous consistency checks that can be listed by
restore. Most
checks are self-explanatory or can “never happen”. Common errors
are given below:
- Converting to new file system format
- A dump tape created from the old file system has been
loaded. It is automatically converted to the new file system format.
- <filename>: not found on tape
- The specified file name was listed in the tape directory,
but was not found on the tape. This is caused by tape read errors while
looking for the file, and from using a dump tape created on an active file
system.
- expected next file <inumber>, got
<inumber>
- A file that was not listed in the directory showed up. This
can occur when using a dump created on an active file system.
- Incremental dump too low
- When doing an incremental restore, a dump that was written
before the previous incremental dump, or that has too low an incremental
level has been loaded.
- Incremental dump too high
- When doing an incremental restore, a dump that does not
begin its coverage where the previous incremental dump left off, or that
has too high an incremental level has been loaded.
- Tape read error while restoring
<filename>
- Tape read error while skipping over inode
<inumber>
- Tape read error while trying to resynchronize
- A tape (or other media) read error has occurred. If a file
name is specified, its contents are probably partially wrong. If an inode
is being skipped or the tape is trying to resynchronize, no extracted
files have been corrupted, though files may not be found on the tape.
- resync restore, skipped <num> blocks
- After a dump read error, restore may have to
resynchronize itself. This message lists the number of blocks that were
skipped over.
EXIT STATUS¶
Restore exits with zero status on success. Tape errors are indicated with
an exit code of 1.
When doing a comparison of files from a dump, an exit code of 2 indicates that
some files were modified or deleted since the dump was made.
ENVIRONMENT¶
If the following environment variable exists it will be utilized by
restore:
- TAPE
- If no -f option was specified, restore will
use the device specified via TAPE as the dump device. TAPE
may be of the form tapename, host:tapename or
user@host:tapename.
- TMPDIR
- The directory given in TMPDIR will be used instead
of /tmp to store temporary files.
- RMT
- The environment variable RMT will be used to
determine the pathname of the remote rmt(8) program.
- RSH
- Restore uses the contents of this variable to
determine the name of the remote shell command to use when doing a network
restore (rsh, ssh etc.). If this variable is not set, rcmd(3) will
be used, but only root will be able to do a network restore.
FILES¶
- /dev/st0
- the default tape drive
- /tmp/rstdir*
- file containing directories on the tape
- /tmp/rstmode*
- owner, mode, and time stamps for directories
- ./restoresymtable
- information passed between incremental restores
SEE ALSO¶
dump(8),
mount(8),
mke2fs(8),
rmt(8)
BUGS¶
Restore can get confused when doing incremental restores from dumps that
were made on active file systems.
A level 0 dump must be done after a full restore. Because
restore runs in
user code, it has no control over inode allocation; thus a full dump must be
done to get a new set of directories reflecting the new inode numbering, even
though the content of the files is unchanged.
The temporary files
/tmp/rstdir* and
/tmp/rstmode* are generated
with a unique name based on the date of the dump and the process ID (see
mktemp(3)), except when
-r or
-R is used. Because
-R allows you to restart a
-r operation that may have been
interrupted, the temporary files should be the same across different
processes. In all other cases, the files are unique because it is possible to
have two different dumps started at the same time, and separate operations
shouldn't conflict with each other.
To do a network restore, you have to run
restore as root or use a remote
shell replacement (see
RSH variable). This is due to the previous
security history of
dump and
restore. (
restore is
written to be setuid root, but we are not certain all bugs are gone from the
code - run setuid at your own risk.)
At the end of restores in
-i or
-x modes (unless
-o option
is in use),
restore will ask the operator whether to set the
permissions on the current directory. If the operator confirms this action,
the permissions on the directory from where
restore was launched will
be replaced by the permissions on the dumped root inode. Although this
behaviour is not really a bug, it has proven itself to be confusing for many
users, so it is recommended to answer 'no', unless you're performing a full
restore and you do want to restore the permissions on '/'.
It should be underlined that because it runs in user code,
restore , when
run with the
-C option, sees the files as the kernel presents them,
whereas
dump sees all the files on a given filesystem. In particular,
this can cause some confusion when comparing a dumped filesystem a part of
which is hidden by a filesystem mounted on top of it.
AUTHOR¶
The
dump/restore backup suite was ported to Linux's Second Extended File
System by Remy Card <card@Linux.EU.Org>. He maintained the initial
versions of
dump (up and including 0.4b4, released in January 1997).
Starting with 0.4b5, the new maintainer is Stelian Pop
<stelian@popies.net>.
AVAILABILITY¶
The
dump/restore backup suite is available from
<
http://dump.sourceforge.net>
HISTORY¶
The
restore command appeared in 4.2BSD.