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 exam-
       ple, 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 load-
       ed 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.  Amre-
              store  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  amre-
              store  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 un-
              derstood 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 .Z or .gz extension
              depending on whether compress or gzip is the preferred  compres-
              sion  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 .RAW 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 hold-
       ing 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-docu-
       mentation: XML-conversion



SEE ALSO

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




                                                                  AMRESTORE(8)

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