topic Re: DDS2 TAPE DRIVE in Operating System - HP-UX

DDS2 TAPE DRIVE

John Howarth_1 — Wed, 23 Feb 2000 02:27:28 GMT

My company has a scsi DDS 2 Tape drive in a unix machine on port 2 and a
database totaling approx 7.2GB, our backup tapes are 8GB 120meter in length,
however the backup is not completeing. If anyone has any ideas or solutions
please could they let me know.

Re: DDS2 TAPE DRIVE

Peter Davies_7 — Wed, 23 Feb 2000 05:40:50 GMT

Hi John,

I had a similar problem myself.

I assume that your backup software has a compression capability, however this
only works when a tape was initially setup for compression when first used. If
the tape has been used previously using none compressed mode, compression won't
work.

You could try and erase (not format) the tape which will return it to the
initial state, this takes ages though (2 or 3 hours per tape). Quick fix would
be to buy a new set of tapes.

Hope this helps

Pete Davies

Re: DDS2 TAPE DRIVE

John Howarth_1 — Wed, 23 Feb 2000 06:29:27 GMT

Tapes are expensive do you know the unix tape format command?

Re: DDS2 TAPE DRIVE

James Shirley_1 — Wed, 23 Feb 2000 07:45:32 GMT

John,

You didn't mention the software you are using for your backup. It would help
if you mention that as well as the device file you use. In any case, I think
DDS2 drives always use hardware compression but I'm not a fan of those
particular drives so don't take that as fact. Are you trying to run software
compression as well? If so, you might try running the backup with software
compression turned off.

Good-luck,
Jim

Re: DDS2 TAPE DRIVE

Roger Sager_1 — Wed, 23 Feb 2000 14:01:04 GMT

G'day John,

Your problem sounds similar to one I had quite a while ago. Currently, we use
HP's Omniback II software which has a GUI front-end to create backup spec etc.
Previously, I used the TAR command to backup to a DLT tape drive instead of our
DDS drive, but regardless the problem was as follows....

I had many mount points that I wish to backup onto tape using the 1m device
driver and on startup of the script it wrote to the tape, but as it went it
seem to get slower and slower. After attempting to backup 20 gig I killed the
process after 10-15 hours..(I forget, but it was a long time). Anyways, what
was occuring was the first set of data would be written, then the tape would
rewind to the beggining, then the next set of data would have to wait as the
tape device read to the end of the fisrt set, then start writing. This rewind,
read ahead, write, then rewind again dragged out and it never seem to finish.

Weeks later I found out if I used the TAR command and a different drive then
the rewind would not occur, but the tape would stop at the end of the 1st
write, then write the 2nd, then the 3rd, and so on.

I hope that helps.

Cheers...Roger Sager