In message "tape backups", ram@cs.arizona.edu writes:
> 
> I recently added an 8mm
> tape (exabyte (8200?) if it matters) drive to my system and I'm trying
> to set up some kind of automatic backup system.

Me too.

> Basically what I am looking for is general ideas on how to cope with
> the rewind on reboot thing. Or for that matter any clever ideas on how
> to create a good backup strategy. What I'd like to do is use one tape
> per week. I figure I can do a level 0 on sunday and do level 1's for
> the rest of the week. If someone has a better idea, please let me
> know.

I was thinking of:
Full backup: rewind tape and write full backup.
Incr backup: rewind tape, fsf past the full, and write an incremental relative
to the last full (not to the last incremental)  (this could be modifed to 
do an incremental relative to the previous incremental by fsf'ing one file
farther into the tape each night.)

But I could not any of the following to work reliably (they would sometimes!):
1) using the non-rewinding device, I could not reliably write another backup
at the position the tape had been left at by the previous backup.
2) rewinding the tape, then fsf'ing to the end of the previous backup
3) writing multiple file marks after a backup finished, then fsf'ing somewhere
into them...

So, I ended up with this solution:

Rewind the tape and do a FULL backup every night, eject the tape on
sunday and replace it with a fresh one (actually just rotate two tapes...)

The drive is only 300MB, and I'm not backing up all the partitions, so it
doesn't take very long... and the machine doesn't have anything useful to
do at 2am anyway...

As for the probe, it goes *faster* for me when there is a tape in the drive,
and goes even faster if it is a warm boot instead of a hard reset or coldstart.

Again, anyone have any ideas?

Tom