Are you running with colocation enabled anywhere?  For best reclaim
performance, I have found that having colocation enabled=yes on both
onsite and offsite pools works the best.  Why?  Reduction of tape mounts.
Cost?  Need more tapes, especially in offsite pool.

Per pool:

Keep in mind that onsite reclamation is 1 process PER tape:  find a tape
needing reclaim->mount tape->relocate data->dismount.

Offsite reclamation is 1 process for ALL tapes:  find all tapes needing
reclaim->select tape x(these appear to be done in age order)->figure out
where all local copies of data are stored->until x is finished(mount
onsite tape->relocate data->dismount onsite->next local tape)->next tape x
(offiste tape)

So it's concievable and likely that one onsite tape could be mounted
several times because some of it's files are on multiple offsite tapes.

Al




"Brazner, Bob" <Bob.Brazner AT JCI DOT COM>
Sent by: "ADSM: Dist Stor Manager" <ADSM-L AT VM.MARIST DOT EDU>
11/11/02 05:44 PM
Please respond to "ADSM: Dist Stor Manager"


        To:     ADSM-L AT VM.MARIST DOT EDU
        cc:
        Subject:        Space reclamation of offsite copy pool takes forever


Reclamation of our offsite copy pool is taking forever.  Right now, we
have
200+ volumes in that pool.  Normally, threshold is set at 60% and I get
maybe 8 or 9 volumes returned after processing for 7 hours (on beefy AIX,
with TSM at 5.1.5).  Lately I've tried setting the threshold at 99, then
98, then 97, etc., but I don't see much improvement in overall freeing up
of tapes.  It appears that most of the time is taken up with mounting
input
volumes.  Even though we have a 3494, I'd say 80% of the time is spent
waiting for tape mounts.  Is there any way to get space reclamation to
free
up offsite tapes faster?  Note, for my onsite tape pool, I do not see this
problem (e.g., I can easily free up 30 tapes in 5 hours or less).

Bob Brazner
Johnson Controls, Inc.
(414) 524-2570