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



NAME
       dump, rdump - incremental file system dump

SYNOPSIS
       /usr/etc/dump [ options [ arguments ] ] filesystem
       /usr/etc/dump [ options [ arguments ] ] filename ...
       /usr/etc/rdump [ options [ arguments ] ] filesystem
       /usr/etc/rdump [ options [ arguments ] ] filename ...

DESCRIPTION
       dump backs up all files in filesystem, or files changed after a certain
       date, or a specified set of files and directories,  to  magnetic  tape,
       diskettes,  or files.  options is a string that specifies dump options,
       as shown below.  Any arguments supplied for specific options are  given
       as  subsequent  words on the command line, in the same order as that of
       the options listed.

       If  dump  is  called  as   rdump,   the   dump   device   defaults   to
       dumphost:/dev/rmt8.

       If no options are given, the default is 9u.

       dump  is  normally  used to back up a complete filesystem.  To restrict
       the dump to a specified set of files and directories on one filesystem,
       list  their  names on the command line.  In this mode the dump level is
       set to 0 and the u option is ignored.

OPTIONS
       0-9    The "dump level."  All files in the filesystem  that  have  been
              modified since the last dump at a lower dump level are copied to
              the volume.  For instance, if you did a "level 2" dump  on  Mon-
              day,  followed  by  a  "level  4"  dump on Tuesday, a subsequent
              "level 3" dump on Wednesday would contain all files modified  or
              added  since  the  "level  2" (Monday) backup.  A "level 0" dump
              copies the entire filesystem to the dump volume.

       a archive-file
              Create a dump table-of-contents archive in the  specified  file,
              archive-file.   This file can be used by restore(8) to determine
              whether a file is present on a dump tape, and if  so,  on  which
              volume it resides.  For further information on the use of a dump
              archive file, see restore(8).

       b factor
              Blocking factor.  Specify the blocking factor for  tape  writes.
              The  default  is 20 blocks per write.  Note: the blocking factor
              is specified in terms of 512  bytes  blocks,  for  compatibility
              with  tar(1).   The default blocking factor for tapes of density
              6250 BPI and greater is 64.  The  default  blocking  factor  for
              cartridge tapes (c option specified) is 126.  The highest block-
              ing factor available with most tape drives is 126.

       c      Cartridge.  Use a cartridge instead of  the  standard  half-inch
              reel.  This sets the density to 1000 BPI, the blocking factor to
              126, and the length to 425 feet.   This  option  also  sets  the
              "inter-record  gap"  to  the appropriate length.  When cartridge
              tapes are used, and this option  is  not  specified,  dump  will
              slightly  miscompute  the size of the tape.  If the b, d, s or t
              options are specified with this option, their values will  over-
              ride the defaults set by this option.

       d bpi  Tape  density.   The  density  of the tape, expressed in BPI, is
              taken from bpi.  This is used to  keep  a  running  tab  on  the
              amount of tape used per reel.  Default densities are:

                     1/2" tape                1600 BPI
                     1/4" cartridge           1000 BPI
                     2.3-Gbyte 8mm tape       54,000 BPI

              Unless  a  higher density is specified explicitly, dump uses its
              default density -- even if the tape drive is capable of  higher-
              density  operation  (for instance, 6250 BPI).  Note: the density
              specified should correspond to the density of  the  tape  device
              being used, or dump will not be able to handle end-of-tape prop-
              erly.  The d option is not compatible with the D option.

       D      Diskette. Specify diskette as the dump media.

       f dump-file
              Dump file.  Use dump-file as the file to  dump  to,  instead  of
              /dev/rmt8.   If dump-file is specified as `-', dump to the stan-
              dard  output.   If  the  file  name  argument  is  of  the  form
              machine:device,  dump  to  a remote machine.  Since dump is nor-
              mally run by root, the name of the local machine must appear  in
              the  .rhosts file of the remote machine.  If the file name argu-
              ment is of the form user@machine:device, dump  will  attempt  to
              execute as the specified user on the remote machine.  The speci-
              fied user must have a .rhosts file on the  remote  machine  that
              allows root from the local machine.  If dump is called as rdump,
              the dump device defaults to dumphost:/dev/rmt8.  To  direct  the
              output to a desired remote machine, set up an alias for dumphost
              in the file /etc/hosts.

       n      Notify.  When this option is specified, if dump requires  atten-
              tion,  it  sends  a terminal message (similar to wall(1)) to all
              operators in the "operator" group.

       s size Specify the size of the volume being dumped to. When the  speci-
              fied  size  is reached, dump waits for you to change the volume.
              dump interprets the specified size as the  length  in  feet  for
              tapes,  and cartridges and as the number of 1024 byte blocks for
              diskettes.  The following are defaults:

                     1/2" tape                2300 feet
                     60-Mbyte 1/4" cartridge  425 feet
                     150-Mbyte 1/4" cartridge 700 feet
                     2.3-Gbyte 8mm            6000 feet
                     diskette                 1422 blocks  (Corresponds  to  a
                                              1.44-Mbyte  diskette,  with  one
                                              cylinder reserved for bad  block
                                              information.)

       t tracks
              Specify the number of tracks for a cartridge tape.  The t option
              is  not  compatible  with  the  D  option.   The  following  are
              defaults:

                     60-Mbyte 1/4" cartridge (Sun2 only)     4 tracks
                     60-Mbyte 1/4" cartridge (all other platforms)
                                                             9 tracks
                     150-Mbyte 1/4" cartridge                18 tracks

       u      Update  the  dump  record.   Add an entry to the file /etc/dump-
              dates, for each filesystem successfully dumped that includes the
              filesystem  name, date, and dump level.  This file can be edited
              by the super-user.

       v      After writing each volume of the dump, the media is rewound  and
              is  verified  against  the filesystem being dumped.  If any dis-
              crepancies are found, dump will respond as if a write error  had
              occurred;  the  operator  will  be asked to mount new media, and
              dump will attempt to rewrite the volume.  Note that  any  change
              to  the filesystem, even the update of the access time on a file
              will cause the verification to fail.  Thus,  the  verify  option
              can only be used on a quiescent filesystem.

       w      List  the filesystems that need backing up.  This information is
              gleaned from the files /etc/dumpdates and /etc/fstab.  When  the
              w  option is used, all other options are ignored.  After report-
              ing, dump exits immediately.

       W      Like w, but includes all filesystems that appear  in  /etc/dump-
              dates, along with information about their most recent dump dates
              and levels.  Filesystems that need backing up are highlighted.

FILES
       /dev/rmt8           default unit to dump to
       dumphost:/dev/rmt8  default remote unit to dump to if called as rdump
       /dev/rst*           Sun386i cartridge tape dump device
       /dev/rfd0a          Sun386i  1.44  megabyte   3.5-inch   high   density
                           diskette drive dump device
       /dev/rfdl0a         Sun386i  720 kilobyte 3.5-inch low density diskette
                           drive dump device
       /dev/rfd0c          Sun386i  1.44  megabyte   3.5-inch   high   density
                           diskette drive dump device
       /dev/rfdl0c         Sun386i  720 kilobyte 3.5-inch low density diskette
                           drive dump device
       /etc/dumpdates      dump date record
       /etc/fstab          dump table: file systems and frequency
       /etc/group          to find group operator
       /etc/hosts

SEE ALSO
       bar(1), fdformat(1), tar(1), wall(1),  dump(5),  fstab(5),  restore(8),
       shutdown(8)

DIAGNOSTICS
       While running, dump emits many verbose messages.

   Exit Codes
       0      Normal exit.
       1      Startup errors encountered.
       3      Abort - no checkpoint attempted.

BUGS
       Fewer than 32 read errors on the file system are ignored.

       Each reel requires a new process, so parent processes for reels already
       written just hang around until the entire tape is written.

       It is recommended that incremental dumps also  be  performed  with  the
       system running in single-user mode.

       dump does not support multi-file multi-volume tapes.

EXAMPLES
       Here  are some examples of arguments which produce satisfactory results
       on a number of typical tape drives.  Note that individual  options  can
       be  in  any  order;   however,  the position of each following argument
       depends on the relative position of each option.

              60-MByte cartridge (Sun2 only): dump cdst 1000 425 4
              60-MByte cartridge:             dump cdst 1000 425 9
              150-MByte cartridge:            dump cdst 1000 700 18
              1/2" tape:                      dump dsb 1600 2300 126
              2.3-GByte 8mm tape:             dump dsb 54000 6000 126

       To make a full dump of a root filesystem on sd3, on  a  150-MByte  car-
       tridge tape st0, use:

              dump 0cdstfu 1000 700 18 /dev/rst0 /dev/sd3a

       To  make and verify an incremental dump at level 5 of the usr partition
       of sd3, on a 1/2" reel tape st1:

              dump 5dsbfuv 1600 2300 126 /dev/rst1 /dev/sd3g

       To make a full backup of the entire disk sd3, on a 2.3-GByte  8mm  tape
       st2, use:

              dump 0dsbfu 54000 6000 126 /dev/rst2 /dev/sd3c

NOTES
   Operator Intervention
       dump requires operator intervention on these conditions: end of volume,
       end of dump, volume write error, volume open error or disk  read  error
       (if  there  are  more than a threshold of 32).  In addition to alerting
       all operators implied by the n option, dump interacts with the operator
       on dump's control terminal at times when dump can no longer proceed, or
       if something is grossly  wrong.   All  questions  dump  poses  must  be
       answered by typing yes or no, as appropriate.

       Since  backing  up  a  disk  can involve a lot of time and effort, dump
       checkpoints at the start of each volume.  If writing that volume  fails
       for  some  reason,  dump will, with operator permission, restart itself
       from the checkpoint after a defective volume has been replaced.

       dump  reports  periodically,  and  in  verbose  fashion.   Each  report
       includes estimates of the percentage of the dump completed and how long
       it will take to complete the dump.  The  estimated  time  is  given  as
       hours:minutes.

   Suggested Dump Schedule
       It  is  vital  to  perform full, "level 0", dumps at regular intervals.
       When performing a full dump, bring the machine down to single-user mode
       using  shutdown(8).  While preparing for a full dump, it is a good idea
       to clean the tape drive and heads.

       Incremental dumps allow for convenient backup and recovery  on  a  more
       frequent basis of active files, with a minimum of media and time.  How-
       ever there are some tradeoffs.  First,  the  interval  between  backups
       should  be  kept  to a minimum (once a day at least).  To guard against
       data loss as a result of a media failure (a rare, but  possible  occur-
       rence),  it  is  a  good idea to capture active files on (at least) two
       sets of dump volumes.  Another consideration  is  the  desire  to  keep
       unnecessary  duplication  of  files  to a minimum to save both operator
       time and media storage.  A third consideration is the ease with which a
       particular  backed-up  version  of  a file can be located and restored.
       The following four-week schedule offers a reasonable  tradeoff  between
       these goals.
                          Sun   Mon   Tue   Wed   Thu   Fri
              Week 1:     Full  5     5     5     5     3
              Week 2:           5     5     5     5     3
              Week 3:           5     5     5     5     3
              Week 4:           5     5     5     5     3

       Although  the  Tuesday -- Friday incrementals contain "extra copies" of
       files from Monday, this scheme assures that any  file  modified  during
       the week can be recovered from the previous day's incremental dump.

   Process Priority of dump
       dump  uses  multiple  processes  to  allow it to read from the disk and
       write to the media  concurrently.   Due  to  the  way  it  synchronizes
       between  these  processes, any attempt to run dump with a nice (process
       priority) of `-5' or better will likely make dump run slower instead of
       faster.



                                7 October 1990                         DUMP(8)