Douglas,

Offsite copy pool space reclamation is usually much slower that onsite
reclamation.  This is because ADSM needs to find the corresponding
onsite copy of the files needed for reclamation and they're usually
spread out over many tapes.  On the other hand, onsite reclamation
processes a volume at a time and doesn't have to deal with all of this
additional overhead..  It  takes ADSM a while to figure out where to
find everything needed for the offsite reclamation process so you'll
usually see it sit there for 30-60 minutes 'thinking' (i.e. not
processing any data).  I've found it helpful not to try to do too much
at once.  For instance if you have 300 offsite tapes and 150 of them
have 50% reclaimable space and you set your reclamation threshold to
50%, its gonna take forever for ADSM process this.  I've had good luck
with processing 20-30 offsite tapes at a time - you can do this by
setting your reclamation threshold much higher.  For instance, you can
set the threshold to 90% on Monday, 80% on Tuesday,  70% on Wednesday,
etc..  While this may involve more tape passes,  it seems that ADSM
handles this better, especially if your reclamation process gets
preempted by a restore and the reclamation needs to restart.  This
method also allows you to 'replenish' your supply of scratch tapes on a
more regular basis.

Tim Pittson
tpittson AT himail.hcc DOT com

>----------
>From:  Douglas A. Backes[SMTP:backed AT MAIL.MODOT.STATE.MO DOT US]
>Sent:  Friday, July 18, 1997 10:13 AM
>To:    ADSM-L AT VM.MARIST DOT EDU
>Subject:       Space Rec. of offiste copy pools
>
> Space reclaimation of our offsite copy pools runs extremely slow.  It takes
>longer than 24 hours to reclaim around 2.5 gig.  Performance is fine on
>Migration, Expiration...etc.
> Does anyone have any ideas or suggestions to speed this up or is this
>normal??
>
>Server -- SP Node
>3494 -- tape lib
>3590 -- tape drives
>SSA Disk
>