I've been trying to weight the advantages of dump and tar.

What I like about tar is I can do a 'tar cz /'  and just backup everything
to one tape (20Gig DLT).

With dump, (if I read the man page correctly) I can only backup one
device-partition per tape, but that incremental backup looks sweet.

However dump seems to try to be smart and assume thing about the media being
written too.
i.e.
> dump -0u -L `date '+%m/%d/%G'` -f /dev/rst0 /
  DUMP: Date of this level 0 dump: Tue Jan  2 13:23:31 2001
  DUMP: Date of last level 0 dump: the epoch
  DUMP: Dumping /dev/rca0a (/) to /dev/rst0
  DUMP: Label: 01/02/2001
  DUMP: mapping (Pass I) [regular files]
  DUMP: mapping (Pass II) [directories]
  DUMP: estimated 46175 tape blocks on 1.18 tape(s).
  DUMP: Volume 1 started at: Tue Jan  2 13:23:48 2001
  DUMP: dumping (Pass III) [directories]
  DUMP: dumping (Pass IV) [regular files]
  DUMP: Closing /dev/rst0
  DUMP: Volume 1 completed at: Tue Jan  2 13:24:19 2001
  DUMP: Volume 1 took 0:00:31
  DUMP: Volume 1 transfer rate: 1236 KB/s
  DUMP: Change Volumes: Mount volume #2
  DUMP: Is the new volume mounted and ready to go?: ("yes" or "no") yes
  DUMP: Volume 2 started at: Tue Jan  2 13:24:22 2001
  DUMP: Volume 2 begins with blocks from inode 324503
  DUMP: 45924 tape blocks on 2 volumes
  DUMP: Volume 2 completed at: Tue Jan  2 13:24:26 2001
  DUMP: Volume 2 took 0:00:04
  DUMP: Volume 2 transfer rate: 1896 KB/s
  DUMP: Date of this level 0 dump: Tue Jan  2 13:23:31 2001
  DUMP: Date this dump completed:  Tue Jan  2 13:24:26 2001
  DUMP: Average transfer rate: 1566 KB/s
  DUMP: level 0 dump on Tue Jan  2 13:23:31 2001
  DUMP: Closing /dev/rst0
  DUMP: DUMP IS DONE

dump guessed I needed 1.18 tapes(20 Gig DLT) to backup:
Filesystem     1K-blocks     Used    Avail Capacity  Mounted on
/dev/ca0a        4049310    44610  3802234     1%    /

Which is quite wrong.

Can you give me some pointers as to what method is the best?

John Maier
Administrator
Midamerica Internet Services
573-446-8881
http://www.midamerica.net
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