AMRESTORE(8)						      System Manager's Manual						      AMRESTORE(8)

NAME

       amrestore - extract backup images from an Amanda tape

SYNOPSIS

       amrestore  [ -r | -c | -C ] [ -b blocksize ] [ -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 expression descibe in the "HOST & DISK EXPRESSION" section of amanda(8).  Datestamp are  special  expres-
       sion  describe  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

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.

       -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 .Z or .gz extension depend-
	      ing  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
	      .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
       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@cs.umd.edu>
       University of Maryland, College Park

SEE ALSO

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

																      AMRESTORE(8)