AIT tape media lifetime?

[X-Post comp.arch.storage, comp.sys.sgi.admin]

We are currently observing tape media errors during our nightly backup
runs. Backup server is a SGI 02, external Sony AIT tape drive.

We started with AIT-1 (Sony SDX-300C) three years ago, 10 Sony
SDX1-25C tapes reused 4 days a week, 8-23GB per tape run (amanda,
backup data go to local disk first and are flushed from there to the
tape drive in one go).

Pi*Daumen makes 4days*52weeks*3.5years/10tapes = 73 reuses of the
individual tape, with varying amount of data dumped on it (1/3 to
nearly full capacity).

Recently the AIT-1 tape drive had hardware errors and was temporarily
replaced by a Sony SDX-500C, no problems.

Then we bought a Sony SDX-500V, which had to be re-jumpered internally
to identify itself as SDX-500C in order to make the OS recognize the
drive (yes, I know I can rebuild the OS to make it recognize the 500V
as well, but I would expect no difference there, no?).

Since we use this new drive, the nightly backup runs very often are
interrupted by
Sep 23 02:52:18 1A:jupiter unix: ALERT: tps1d2 Unrecoverable media error

I tried to flush the data manually onto that tape: I/O error.
Cleaning the tape via cleaning cartridge made no difference.

Then I connected the SDX-500C, flushed the data onto that very same
tape: no problem.

I connected the SDX-500V again, read the data back from that tape, no
problem (checksums match). Then I flushed the data again onto the
tape using the SDX-500V: tape write error: I/O error.

My question is: are the tape media really at the end of their
lifetime, or is the new drive a bit picky? 3.5 years seems not so
much to me when the archival time is said to be 30 years. I found
little data on the reusability of tapes, only a mention of 30000
end-to-end passes (whatever that means) for AIT-1 on
http://www.array.at/sony/ait.htm, so to me it looks like the tapes
should still be ok.

Or does it really make a difference whether the SDX-500V tape drive is
rejumpered to identify itself as 500C instead of 500V?

Thanks for any experience, opinions or further test strategies.
R'

Le Thu, 23 Sep 2004 16:31:03 +0200, Ralf Fassel a écrit*:


Or does it really make a difference whether the SDX-500V tape drive is
rejumpered to identify itself as 500C instead of 500V?

It's probably not really working as expected... YOu probably should try to
recompile your stuff to get it recognized natively and see what' hapenning.

--
Je suis riche des biens dont je sais me passer.
Louis-Jean-Baptiste Etienne Vigée.

* Ralf Fassel
| My question is: are the tape media really at the end of their
| lifetime, or is the new drive a bit picky?

The preliminary answer seems to be to get a replacement drive from
Sony. They sent us a new one w/o problems, and so far it works w/o
problems.

R'