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DUMP(1M)                                                              DUMP(1M)



NAME
       dump - incremental file system dump

SYNOPSIS
       dump [ key [ argument ... ] filesystem ]

DESCRIPTION
       Dump  copies to magnetic tape all files changed after a certain date in
       the filesystem.  The key specifies the date and other options about the
       dump.  Key consists of characters from the set 0123456789fusd.

       f    Place the dump on the next argument file instead of the tape.

       u    If  the  dump completes successfully, write the date of the begin-
            ning of the dump on file `/etc/ddate'.  This file records a  sepa-
            rate date for each filesystem and each dump level.

       0-9  This  number  is  the  `dump level'.  All files modified since the
            last date stored in the file `/etc/ddate' for the same  filesystem
            at  lesser levels will be dumped.  If no date is determined by the
            level, the beginning of time is assumed; thus the option 0  causes
            the entire filesystem to be dumped.

       s    The  size  of  the  dump tape is specified in feet.  The number of
            feet is taken from the next argument.  When the specified size  is
            reached,  the dump will wait for reels to be changed.  The default
            size is 2300 feet.

       d    The density of the tape, expressed in BPI, is taken from the  next
            argument.  This is used in calculating the amount of tape used per
            write. The default is 1600.

       If no arguments are given, the key is assumed to be 9u  and  a  default
       file system is dumped to the default tape.

       Now a short suggestion on how perform dumps.  Start with a full level 0
       dump

            dump 0u

       Next, periodic level 9 dumps should be made on an exponential  progres-
       sion  of tapes.  (Sometimes called Tower of Hanoi - 1 2 1 3 1 2 1 4 ...
       tape 1 used every other time, tape 2 used every  fourth,  tape  3  used
       every eighth, etc.)

            dump 9u

       When the level 9 incremental approaches a full tape (about 78000 blocks
       at 1600 BPI blocked 20), a level 1 dump should be made.

            dump 1u

       After this, the exponential series should  progress  as  uninterrupted.
       These level 9 dumps are based on the level 1 dump which is based on the
       level 0 full dump.  This progression of levels of dump can  be  carried
       as far as desired.

FILES
       default filesystem and tape vary with installation.
       /etc/ddate: record dump dates of filesystem/level.

SEE ALSO
       restor(1), dump(5), dumpdir(1)

DIAGNOSTICS
       If  the  dump  requires  more  than one tape, it will ask you to change
       tapes.  Reply with a new-line when this has been done.

BUGS
       Sizes are based on 1600 BPI blocked tape.  The raw magtape  device  has
       to  be used to approach these densities.  Read errors on the filesystem
       are ignored.  Write errors on the magtape are usually fatal.



                                                                      DUMP(1M)