amrestore

AMRESTORE(8)                                                      AMRESTORE(8)



NAME
       amrestore - extract backup images from an Amanda tape

SYNOPSIS
       amrestore [-r -c -C] [-b blocksize] [-f fileno] [-l label] [-p] [-h]
                 tapedevice holdingfile
                 [hostname [diskname [datestamp [hostname [diskname [datestamp...]]]]]]

DESCRIPTION
       Amrestore extracts backup images from the tape mounted on tapedevice or
       from the holding disk file holdingfile that match hostname, diskname
       and datestamp patterns given on the command line. The tape or holding
       file must be in a format written by the amdump or amflush program.

       If diskname is not specified, all backups on the tape for the previous
       hostname are candidates. If datestamp is not specified, all backups on
       the tape for the previous hostname and diskname are candidates. If no
       hostname, diskname or datestamp are specified, every backup on the tape
       is a candidate.

       Hostname and diskname are special expressions described in the "HOST &
       DISK EXPRESSION" section of amanda(8).  Datestamp are special
       expression described in the "DATESTAMP EXPRESSION" section of
       amanda(8). For example, if diskname is "rz[23]a", it would match disks
       rz2a and rz3a.

       Datestamp is useful if amflush writes multiple backup runs to a single
       tape.

       Unless -p is used, candidate backup images are extracted to files in
       the current directory named:

       hostname.diskname.datestamp.dumplevel

       Amrestore doesn't use a changer, it restore from the tape already
       loaded in the tapedevice.

OPTIONS
       -b     Set the blocksize used to read the tape or holding file. All
              holding files must be read with a blocksize of 32 KBytes.
              Amrestore should normally be able to determine the blocksize for
              tapes on its own and not need this parameter.

       The default is 32 KBytes.

       -f     Do a rewind followed by a fsf <fileno> before trying to restore
              an image.

       -l     Check if we restoring from the tape with the right label

       -p     Pipe output. The first matching backup image is sent to standard
              output, which is normally a pipe to restore or tar, then
              amrestore quits. It may be run again to continue selecting
              backups to process. Make sure you specify the no-rewind
              tapedevice when doing this.

       Note: restore may report "short read" errors when reading from a pipe.
       Most versions of restore support a blocking factor option to let you
       set the read block size, and you should set it to 2. See the example
       below.

       -c     Compress output using the fastest method the compression program
              provides.  Amrestore normally writes output files in a format
              understood by restore or tar, even if the backups on the tape
              are compressed. With the -c or -C option, amrestore writes all
              files in compressed format, even if the backups on the tape are
              not compressed. Output file names will have a or extension
              depending on whether compress or gzip is the preferred
              compression program. This option is useful when the current
              directory disk is small.

       -C     Compress output using the best method the compression program
              provides (may be very CPU intensive). See the notes above about
              the -c option.

       -r     Raw output. Backup images are output exactly as they are on the
              tape, including the amdump headers. Output file names will have
              a extension. This option is only useful for debugging and other
              strange circumstances.

       -h     Header output. The tape header block is output at the beginning
              of each file. This is like -r except -c or -C may also be used
              to compress the result.  Amrecover uses the header to determine
              the restore program to use.

       If a header is written (-r or -h), only 32 KBytes are output regardless
       of the tape blocksize. This makes the resulting image usable as a
       holding file.

EXAMPLES
       The following does an interactive restore of disk rz3g from host seine,
       to restore particular files. Note the use of the b option to restore,
       which causes it to read in units of two 512-byte blocks (1 Kbyte) at a
       time. This helps keep it from complaining about short reads.


       % amrestore -p /dev/nrmt9 seine rz3g | restore -ivbf 2 -



       The next example extracts all backup images for host seine. This is the
       usual way to extract all data for a host after a disk crash.


       % amrestore /dev/nrmt9 seine



       If the backup datestamp in the above example is 19910125 and seine has
       level 0 backups of disks rz1a and rz1g on the tape, these files will be
       created in the current directory:


       seine.rz1a.19910125.0
       seine.rz1g.19910125.0



       You may also use amrestore to extract a backup image from a holding
       disk file that has not yet been flushed to tape:


       % amrestore -p /amanda/20001119/seine.rz1a.2 | restore -ivbf 2 -



       Amrestore may be used to generate a listing of images on a tape:


       % mt -f /dev/nrmt9 rewind
       % amrestore -p /dev/nrmt9 no-such-host > /dev/null



       This asks amrestore to find images for host no-such-host. It will not
       find any entries that match, but along the way will report each image
       it skips.

CAVEATS
       GNU-tar must be used to restore files from backup images created with
       the GNUTAR dumptype. Vendor tar programs sometimes fail to read GNU tar
       images.

AUTHOR
       James da Silva, <jds@amanda.org>, University of Maryland, College Park:
       Original text

       Stefan G. Weichinger, <sgw@amanda.org>, maintainer of the Amanda-
       documentation: XML-conversion

SEE ALSO
       amanda(8), amdump(8), amflush(8), tar(1)restore(8)




                                                                  AMRESTORE(8)