There are a few reasons.
We have this happen all the time since we have 100+ tapes on the shelf
(old soon to be retired system).
1:  If a copypool tape is running reclamation it may need a "TAPEPOOL"
tape to copy data to create the new "COPYPOOL / off-site" tape.
2:  After a while expiration runs and the tape is no longer 100% full,
it reaches the "reclamation" threshhold and runs reclamation to free up
that tape.
3:  A restore needs that tape and the data is not in the library.

Eric

-----Original Message-----
From: ADSM: Dist Stor Manager [mailto:ADSM-L AT VM.MARIST DOT EDU] On Behalf Of
Dave Zarnoch
Sent: Tuesday, May 24, 2005 8:41 AM
To: ADSM-L AT VM.MARIST DOT EDU
Subject: Confused about reclamation

Folks,

I'm a little confused about space reclamation...

I ran out of empty slots in my silo so I had to move some tapes
to a shelf location.

I was really careful to only move tapes that TSM says are "full"
and 100% utilized.

I now see a request for one of those tapes for space reclamation.

1 - Why is TSM calling for this tape?

2 - Should I mark all of my tapes on the shelf as "unavailable"?
     (I hesitate to do this because of problems that may occur if a
restore
      is called that needs this tape)

3 - What will happen when expiration runs?
     (Will the tapes be called for?)

Thanks!

DaveZ