ADSM-L

Re: Tape TTL

2006-10-18 08:17:04
Subject: Re: Tape TTL
From: Richard Sims <rbs AT BU DOT EDU>
To: ADSM-L AT VM.MARIST DOT EDU
Date: Wed, 18 Oct 2006 08:15:43 -0400
On Oct 18, 2006, at 7:44 AM, Lars-Erik Öhman wrote:

Library: 3584
Drives: 3592

Have been looking for any recommendations about how long I could use a tape before it´s necessary to change them to new ones. I know that it´s up to how much a tape have been used, mounted, read, written and whatever. Or is it ok to use a tape until it failures?

Below is details about 2 of my tapes, where 000051 is more typical of the most of my tapes, and 000007 is very rare in my library. How come that the most of my tapes are only mounted between 5 and 20 times since 1,5 years back? I do backup between 450 and 600 Gb a night.

Hello, Larsa -

I believe that most of us use tapes until they consistently demonstrate problems, over multiple good drives. You can use tapeutil to exercise and test a questionable, checked-out tape. The TapeAlert facility may help with this. And, of course, when you find a Filling tape marked Readonly, you know there was a problem; similarly when a tape is Unavailable.

TSM tracks tape statistics while the tape is in a storage pool, as is apparent in Query Volume reporting only tapes in storage pools. Scratch rotation causes the accumulated values to be discarded. If you want long-range statistical tracking by TSM, you should assign volumes to storage pools via DEFine Volume. Beyond TSM, libraries may keep track of the number of times a volume is mounted, as does the 3494. And modern tape technology uses Cartridge Memory, which tracks usage (but not that it's readily retrievable by customers).

Keep in mind also that the report number labeled with "Number of Times Mounted" has a misleading name: it is actually the number of times that a tape was opened for reading or writing when it was mounted on a drive.

   Richard Sims

<Prev in Thread] Current Thread [Next in Thread>