Subject: Re: Tape Backups -- tar vs. dump
To: John Maier <>
From: Frederick Bruckman <>
List: netbsd-users
Date: 01/02/2001 14:04:21
On Tue, 2 Jan 2001, John Maier wrote:

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

Per "file" (tape "file"), actually. So if you use "-f /dev/nrst0" (or
leave it off -- nrst0 is the default device), you can backup several
partitions at once by listing them all on the command line. For the
restore, you use the "-s" argument to choose which "file" to restore.

> > dump -0u -L `date '+%m/%d/%G'` -f /dev/rst0 /


  dump -0u -B 20000000 / /usr /home; eject tape

Then, to sanity test your backup, reinsert tape

  cd /tmp; restore -i -s 3

and select a file from /home, etc. Some admins don't trust the
"no-rewind" tape device, and say they'd rather use three tapes to
backup three partitions. That's because if anyone ejects the tape
between backups, game over; the next backup is going to the beginning.
For my money, it's safe enough if you lay them down all at once, as
above, but it depends an your needs.