amrestore - extract backup images from an Amanda tape


SYNOPSIS

       amrestore  [  -r  |  -c  | -C ] [ -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 file holdingfile that match
       hostname,  diskname  and  datestamp  patterns given on the
       command line.  The tape or holding file must be in a  for­
       mat 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 host­
       name  and  diskname  are  candidates.   If  no   hostname,
       diskname  or  datestamp are specified, every backup on the
       tape is a candidate.

       Hostname, diskname and datestamp are  regular  expressions
       that  may  match  more  than  one backup.  For example, if
       diskname is "rz[23]a", it would match disks rz2a and rz3a.
       Hostname,  diskname  or  datestamp  may be an empty string
       ("") to match every host, disk or date (this  is  just  an
       abbreviation for ".*").

       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

       -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 sup­
              port 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  com­
              pression   program  provides.   Amrestore  normally
              writes output  files  in  a  format  understood  by

              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  compres­
              sion  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.


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 -

       James da Silva <jds@cs.umd.edu>
       University of Maryland, College Park


SEE ALSO

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


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