Matthew,
        Reclamation basically invokes Move Data 'under the covers'.  It's
behavior is affected by whether collocation is enabled or not and how
many, if any scratch tapes, are available.  If collocation is enabled
but you don't have enough tapes to honor collocation (i.e. 40 clients /
25 tapes), then things will work a little differently   However, if
scratch tapes are plentiful,  this is how it would work.   If  Node 'A'
has the following tapes

1) C00001    25%     Status=Full
2) C00532    30%     Status=Full
3) C00212    12%     Status=Filling

And you set the reclamation threshold to 50%, the contents of C00001 and
C00532 will be copied to C00212 (it's status is filling) and you'll end
up with 1 tape that's about 67% full.  Note - I don't remember whether
this behavior would change if you allowed multiple reclamation processes
to run concurrently against the same storage pool.

It is possible to do space reclamation using move data commands.  I
frequently use the Move Data command to clear off onsite tapes with a
high % reclaimable space (90% +)., moving the data back to the disk
storagepool.  This allows us to reclaim a lot of tapes in a short period
of time.

Tim Pittson
tpittson AT himail.hcc DOT com

>----------
>From:  Matthew Warren[SMTP:mwarren AT OSMF.BT.CO DOT UK]
>Reply To:      ADSM: Dist Stor Manager
>Sent:  Tuesday, September 23, 1997 11:10 AM
>To:    ADSM-L AT VM.MARIST DOT EDU
>Subject:       MOVE DATA Questions
>
>Hello all,
>
>        I have some questions regarding MOVE DATA commands.
>
>Imagine I have 3 tape volumes.
>
>B       60% full.
>C       10% full.
>D       0%  full. (Any scratch)
>
>
>
>Is it possible to movedata from B to D then C to D and end up with B & C at
>0% and D at 70% thereby emulating space reclamation?
>
>
>OR
>
>
>Does ADSM always ask for a new scratch tape when a move data is performed so
>I will end up with
>
>(Assuming movedata for b is done THEN movedata for C)
>
>B       0%  full
>C       0%  full
>D       60% full
>E       10% full
>
>
>
>Basically, Is it possible to do any kind of space reclaim using on or offsite
>move data cammonds?
>
>
>
>I dont think so, but a colleague of mine does. If the argument settles in my
>favour I'll buy you a virtual pint!
>
>
>
>Matthew Warren.
>BT Open Systems Storage Managment.
>
>mwarren AT osmf.bt.co DOT uk
>