Provided by: dump_0.4b44-1ubuntu1_i386 bug

NAME

       dump - ext2/3/4 filesystem backup

SYNOPSIS

       dump  [-level#]  [-ackMnqSuv] [-A file] [-B records] [-b blocksize] [-d
       density] [-D file] [-e inode numbers] [-E file] [-f file]  [-F  script]
       [-h  level]  [-I  nr errors] [-jcompression level] [-L label] [-Q file]
       [-s feet] [-T date] [-y] [-zcompression level] files-to-dump

       dump [-W | -w]

DESCRIPTION

       Dump examines files on an  ext2/3/4  filesystem  and  determines  which
       files  need  to be backed up. These files are copied to the given disk,
       tape or other storage medium for safe keeping (see the -f option  below
       for doing remote backups). A dump that is larger than the output medium
       is broken into multiple volumes. On most media the size  is  determined
       by writing until an end-of-media indication is returned.

       On  media  that cannot reliably return an end-of-media indication (such
       as some cartridge tape drives), each volume is of  a  fixed  size;  the
       actual  size  is  determined  by specifying cartridge media, or via the
       tape size, density and/or block count options below.  By  default,  the
       same  output  file  name  is  used  for each volume after prompting the
       operator to change media.

       files-to-dump is either a mountpoint of a filesystem or a list of files
       and  directories  to  be  backed up as a subset of a filesystem. In the
       former case, either the path to a mounted filesystem or the  device  of
       an  unmounted  filesystem  can  be  used.  In  the latter case, certain
       restrictions are placed on the backup: -u is not allowed, the only dump
       level  that  is  supported  is 0 and all the files and directories must
       reside on the same filesystem.

OPTIONS

       The following options are supported by dump:

       -level#
              The dump level (any integer). A level 0, full backup,  specified
              by  -0 guarantees the entire file system is copied (but see also
              the -h option  below).  A  level  number  above  0,  incremental
              backup,  tells  dump to copy all files new or modified since the
              last dump of a lower level. The default level is 0. Historically
              only  levels 0 to 9 were usable in dump, this version is able to
              understand any integer as a dump level.

       -a     "auto-size". Bypass all  tape  length  calculations,  and  write
              until  an  end-of-media indication is returned.  This works best
              for most modern tape drives, and is the  default.  Use  of  this
              option is particularly recommended when appending to an existing
              tape, or using a tape drive with hardware compression (where you
              can never be sure about the compression ratio).

       -A archive_file
              Archive  a  dump table-of-contents in the specified archive_file
              to be used by restore(8) to determine whether a file is  in  the
              dump file that is being restored.

       -b blocksize
              The  number  of kilobytes per dump record. The default blocksize
              is 10, unless the -d option has been  used  to  specify  a  tape
              density  of 6250BPI or more, in which case the default blocksize
              is 32. Th maximal value is 1024.  Note however that,  since  the
              IO system slices all requests into chunks of MAXBSIZE (which can
              be as low as 64kB), you can experience problems with dump(8) and
              restore(8)  when  using a higher value, depending on your kernel
              and/or libC versions.

       -B records
              The number of 1 kB blocks per volume. Not normally required,  as
              dump  can  detect  end-of-media.  When  the  specified  size  is
              reached, dump waits for you to change the volume.   This  option
              overrides  the  calculation  of  tape  size  based on length and
              density. If compression is  on  this  limits  the  size  of  the
              compressed output per volume.  Multiple values may be given as a
              single argument separated by commas.  Each value  will  be  used
              for  one  dump  volume in the order listed; if dump creates more
              volumes than the number of values given, the last value will  be
              used  for  the  remaining volumes. This is useful for filling up
              already partially filled media (and then  continuing  with  full
              size volumes on empty media) or mixing media of different sizes.

       -c     Change  the defaults for use with a cartridge tape drive, with a
              density of 8000 bpi, and a length of  1700  feet.  Specifying  a
              cartridge drive overrides the end-of-media detection.

       -d density
              Set tape density to density.  The default is 1600BPI. Specifying
              a tape density overrides the end-of-media detection.

       -D file
              Set the path name of the file storing the information about  the
              previous  full  and  incremental  dumps. The default location is
              /var/lib/dumpdates.

       -e inodes
              Exclude inodes from the dump. The inodes parameter  is  a  comma
              separated list of inode numbers (you can use stat(1) to find the
              inode number for a file or directory).

       -E file
              Read list of inodes to be excluded from the dump from  the  text
              file  file.  The file file should be an ordinary file containing
              inode numbers separated by newlines.

       -f file
              Write the backup to file; file may be a special device file like
              /dev/st0  (a  tape  drive), /dev/rsd1c (a floppy disk drive), an
              ordinary file, or - (the standard output). Multiple  file  names
              may be given as a single argument separated by commas. Each file
              will be used for one dump volume in the  order  listed;  if  the
              dump  requires  more volumes than the number of names given, the
              last file  name  will  used  for  all  remaining  volumes  after
              prompting  for  media changes. If the name of the file is of the
              form host:file or user@host:file dump writes to the  named  file
              on  the  remote  host  (which should already exist, dump doesn't
              create a new remote file) using rmt(8).  The default  path  name
              of the remote rmt(8) program is /etc/rmt; this can be overridden
              by the environment variable RMT.

       -F script
              Run script at the end of each tape (except for  the  last  one).
              The  device name and the current volume number are passed on the
              command line. The script must return 0 if dump  should  continue
              without  asking  the  user  to change the tape, 1 if dump should
              continue but ask the user to change the  tape.  Any  other  exit
              code  will  cause  dump  to  abort.  For  security reasons, dump
              reverts back to the real user ID and the real  group  ID  before
              running the script.

       -h level
              Honor  the user nodump flag UF_NODUMP only for dumps at or above
              the given  level.   The  default  honor  level  is  1,  so  that
              incremental  backups  omit  such  files  but full backups retain
              them.

       -I nr errors
              By default, dump will ignore the first 32  read  errors  on  the
              file  system  before  asking  for operator intervention. You can
              change this using this flag to any value. This  is  useful  when
              running  dump  on  an active filesystem where read errors simply
              indicate  an  inconsistency  between  the  mapping  and  dumping
              passes.

              A value of 0 means that all read errors will be ignored.

       -jcompression level
              Compress  every  block  to  be  written  on the tape using bzlib
              library. This option will work only when dumping to  a  file  or
              pipe  or,  when  dumping  to  a tape drive, if the tape drive is
              capable of writing variable length  blocks.  You  will  need  at
              least  the  0.4b24  version  of  restore  in  order  to  extract
              compressed tapes. Tapes written using compression  will  not  be
              compatible  with  the  BSD tape format. The (optional) parameter
              specifies the compression level  bzlib  will  use.  The  default
              compression  level is 2. If the optional parameter is specified,
              there should be no white space between the option letter and the
              parameter.

       -k     Use  Kerberos  authentication  to  talk  to remote tape servers.
              (Only available  if  this  option  was  enabled  when  dump  was
              compiled.)

       -L label
              The  user-supplied  text  string  label  is placed into the dump
              header, where tools like restore(8) and file(8) can  access  it.
              Note that this label is limited to be at most LBLSIZE (currently
              16) characters, which must include the terminating \0.

       -m     If this flag is specified, dump will  optimise  the  output  for
              inodes  having been changed but not modified since the last dump
              ('changed' and 'modified' have the meaning defined in stat(2) ).
              For  those  inodes, dump will save only the metadata, instead of
              saving the entire  inode  contents.   Inodes  which  are  either
              directories  or have been modified since the last dump are saved
              in a regular way. Uses of this flag must be consistent,  meaning
              that either every dump in an incremental dump set have the flag,
              or no one has it.

              If you use this option, be aware that many programs that  unpack
              files  from archives (e.g. tar, rpm, unzip, dpkg) may set files'
              mtimes to dates in the past.  Files installed in  this  way  may
              not be dumped correctly using "dump -m" if the modified mtime is
              earlier than the previous level dump.

              Tapes written using such 'metadata  only'  inodes  will  not  be
              compatible  with  the  BSD  tape  format  or  older  versions of
              restore.

       -M     Enable the multi-volume feature. The name specified  with  f  is
              treated  as a prefix and dump writes in sequence to <prefix>001,
              <prefix>002 etc. This can be useful when dumping to files on  an
              ext2/3/4  partition,  in  order  to  bypass  the  2GB  file size
              limitation.

       -n     Whenever dump requires operator attention, notify all  operators
              in the group operator by means similar to a wall(1).

       -q     Make  dump  abort  immediately  whenever  operator  attention is
              required, without  prompting  in  case  of  write  errors,  tape
              changes etc.

       -Q file
              Enable  the  Quick  File Access support. Tape positions for each
              inode are stored into the file file which is used by restore (if
              called  with parameter -Q and the filename) to directly position
              the tape at the file restore is currently working on. This saves
              hours  when restoring single files from large backups, saves the
              tapes and the drive's head.

              It is recommended to set up the st driver to return logical tape
              positions  rather than physical before calling dump/restore with
              parameter -Q.  Since not all tape devices support physical  tape
              positions those tape devices return an error during dump/restore
              when the st driver is  set  to  the  default  physical  setting.
              Please  see  the  st(4) man page, option MTSETDRVBUFFER , or the
              mt(1) man page, on how to set the driver to return logical  tape
              positions.

              Before  calling  restore with parameter -Q, always make sure the
              st driver is set to return the same type of tape  position  used
              during the call to dump.  Otherwise restore may be confused.

              This  option can be used when dumping to local tapes (see above)
              or to local files.

       -s feet
              Attempt to calculate the amount of tape needed at  a  particular
              density.  If  this  amount  is  exceeded, dump prompts for a new
              tape. It is recommended to be a bit conservative on this option.
              The  default  tape length is 2300 feet. Specifying the tape size
              overrides end-of-media detection.

       -S     Size estimate. Determine the amount of space that is  needed  to
              perform  the  dump  without  actually  doing it, and display the
              estimated number of bytes it will  take.  This  is  useful  with
              incremental dumps to determine how many volumes of media will be
              needed.

       -T date
              Use the specified date as the starting time for the dump instead
              of the time determined from looking in /var/lib/dumpdates .  The
              format of date is the same as that of ctime(3)  followed  by  an
              rfc822  timezone  specification:  either  a  plus  or minus sign
              followed by two digits for the number of hours  and  two  digits
              for  the  minutes.   For  example, -0800 for eight hours west of
              Greenwich or +0230 for two hours and a half east  of  Greenwich.
              This  timezone  offset  takes into account daylight savings time
              (if applicable to  the  timezone):  UTC  offsets  when  daylight
              savings  time  is  in effect will be different than offsets when
              daylight  savings  time  is  not   in   effect.   For   backward
              compatibility,  if  no  timezone  is  specified, a local time is
              assumed.  This option is useful for automated dump scripts  that
              wish  to  dump  over a specific period of time. The -T option is
              mutually exclusive from the -u option.

       -u     Update the file /var/lib/dumpdates after a successful dump.  The
              format  of  /var/lib/dumpdates is readable by people, consisting
              of one free format record per line: filesystem  name,  increment
              level  and  ctime(3)  format  dump  date  followed  by  a rfc822
              timezone specification (see the -u option for  details).  If  no
              timezone  offset  is  specified, times are interpreted as local.
              Whenever the  file  is  written,  all  dates  in  the  file  are
              converted  to  the  local  time  zone,  without changing the UTC
              times. There may be only one entry per filesystem at each level.
              The  file  /var/lib/dumpdates may be edited to change any of the
              fields, if necessary.

       -v     The -v (verbose) makes dump to  print  extra  information  which
              could be helpful in debug sessions.

       -W     Dump  tells  the  operator  what file systems need to be dumped.
              This information is gleaned from  the  files  /var/lib/dumpdates
              and /etc/fstab.  The -W option causes dump to print out, for all
              file systems in /var/lib/dumpdates , and recognized file systems
              in  /etc/mtab  and  /etc/fstab.   the  most recent dump date and
              level, and highlights those that should be  dumped.  If  the  -W
              option  is  set,  all  other options are ignored, and dump exits
              immediately.

       -w     Is like -W, but prints only recognized filesystems in  /etc/mtab
              and /etc/fstab which need to be dumped.

       -y     Compress  every  block  to  be written to the tape using the lzo
              library.  This doesn't compress as well as the zlib library  but
              it's  much faster.  This option will work only when dumping to a
              file or pipe or, when dumping to a tape drive, if the tape drive
              is  capable of writing variable length blocks.  You will need at
              least  the  0.4b34  version  of  restore  in  order  to  extract
              compressed  tapes.  Tapes  written using compression will not be
              compatible with the BSD tape format.

       -zcompression level
              Compress every block to  be  written  on  the  tape  using  zlib
              library.  This  option  will work only when dumping to a file or
              pipe or, when dumping to a tape drive,  if  the  tape  drive  is
              capable  of  writing  variable  length  blocks. You will need at
              least  the  0.4b22  version  of  restore  in  order  to  extract
              compressed  tapes.  Tapes  written using compression will not be
              compatible with the BSD tape format.  The  (optional)  parameter
              specifies  the  compression  level  zlib  will  use. The default
              compression level is 2. If the optional parameter is  specified,
              there should be no white space between the option letter and the
              parameter.

       Dump requires operator intervention on these conditions: end  of  tape,
       end  of  dump, tape write error, tape open error or disk read error (if
       there is more than a threshold of nr errors). In addition  to  alerting
       all  operators  implied by the -n key, 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", appropriately.

       Since making a dump involves a lot of time and effort for  full  dumps,
       dump  checkpoints  itself  at the start of each tape volume. If writing
       that volume fails for some reason, dump will, with operator permission,
       restart  itself from the checkpoint after the old tape has been rewound
       and removed, and a new tape has been mounted.

       Dump tells the  operator  what  is  going  on  at  periodic  intervals,
       including  usually  low estimates of the number of blocks to write, the
       number of tapes it will take, the time to completion, and the  time  to
       the  tape  change.  The output is verbose, so that others know that the
       terminal controlling dump is busy, and will be for some time.

       In the event of a catastrophic disk event, the time required to restore
       all  the  necessary  backup  tapes  or  files  to disk can be kept to a
       minimum by staggering the incremental dumps.  An  efficient  method  of
       staggering incremental dumps to minimize the number of tapes follows:

       --     Always start with a level 0 backup, for example:
                     /sbin/dump -0u -f /dev/st0 /usr/src

              This  should  be done at set intervals, say once a month or once
              every two months, and on a set of  fresh  tapes  that  is  saved
              forever.

       --     After  a  level  0,  dumps of active file systems are taken on a
              daily basis, with this sequence of dump levels:
                     3 2 5 4 7 6 9 8 9 9 ...

              For the daily dumps, it should be possible to use a fixed number
              of  tapes  for  each  day,  used on a weekly basis. Each week, a
              level 1 dump is taken, and  the  daily  Hanoi  sequence  repeats
              beginning  with  3. For weekly dumps, another fixed set of tapes
              per dumped file system is used, also on a cyclical basis.

       After several months or so, the  daily  and  weekly  tapes  should  get
       rotated out of the dump cycle and fresh tapes brought in.

       Another  backup  strategy  is the Tower of Hanoi sequence, which reuses
       older tapes in a way that for newer dates the available restore  points
       are     more     frequent,     then     for     older     dates    (see
       http://en.wikipedia.org/wiki/Backup_rotation_scheme   for    additional
       information).

       (The 4.3BSD option syntax is implemented for backward compatibility but
       is not documented here.)

ENVIRONMENT

       TAPE   If no  -f  option  was  specified,  dump  will  use  the  device
              specified  via TAPE as the dump device.  TAPE may be of the form
              tapename, host:tapename, or user@host:tapename.

       RMT    The environment variable RMT  will  be  used  to  determine  the
              pathname of the remote rmt(8) program.

       RSH    Dump uses the contents of this variable to determine the name of
              the remote shell command to use when doing remote backups  (rsh,
              ssh  etc.).  If  this variable is not set, rcmd(3) will be used,
              but only root will be able to do remote backups.

FILES

       /dev/st0
              default tape unit to dump to

       /var/lib/dumpdates
              dump date records

       /etc/fstab
              dump table: file systems and frequency

       /etc/mtab
              dump table: mounted file systems

       /etc/group
              to find group operator

SEE ALSO

       fstab(5), restore(8), rmt(8)

DIAGNOSTICS

       Many, and verbose.

COMPATIBILITY

       The format of  the  /var/lib/dumpdates  file  has  changed  in  release
       0.4b34, however, the file will be read correctly with either pre-0.4b34
       or 0.4b34 and later versions of dump provided that the machine on which
       dump  is  run  did  not change timezones (which should be a fairly rare
       occurrence).

EXIT STATUS

       Dump exits with zero status on success. Startup  errors  are  indicated
       with  an exit code of 1; abnormal termination is indicated with an exit
       code of 3.

BUGS

       It might be considered a bug that this version of dump can only  handle
       ext2/3/4   filesystems.   Specifically,  it  does  not  work  with  FAT
       filesystems.

       Fewer than 32 read errors (change this with -I) on the  filesystem  are
       ignored. If noticing read errors is important, the output from dump can
       be parsed to look for lines that contain the text 'read error'.

       When a read error occurs, dump prints out  the  corresponding  physical
       disk  block and sector number and the ext2/3/4 logical block number. It
       doesn't print out the corresponding file name or even the inode number.
       The user has to use debugfs(8), commands ncheck and icheck to translate
       the ext2blk number printed out by dump into an inode number, then  into
       a file name.

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

       The estimated number of tapes is not correct if compression is on.

       It would be nice if dump knew about the dump sequence,  kept  track  of
       the tapes scribbled on, told the operator which tape to mount when, and
       provided more assistance for the operator running restore.

       Dump cannot do remote backups without being run as  root,  due  to  its
       security  history.   Presently,  it works if you set it setuid (like it
       used to be), but this might constitute a security risk. Note  that  you
       can set RSH to use a remote shell program instead.

AUTHOR

       The  dump/restore  backup  suite  was ported to Linux's Second Extended
       File System by Remy Card <card@Linux.EU.Org>. He maintained the initial
       versions of dump (up and including 0.4b4, released in January 1997).

       Starting    with   0.4b5,   the   new   maintainer   is   Stelian   Pop
       <stelian@popies.net>.

AVAILABILITY

       The     dump/restore     backup     suite     is     available     from
       <http://dump.sourceforge.net>

HISTORY

       A dump command appeared in Version 6 AT&T UNIX.