I have experience the same performance using AIX server and 7331 8mm
tape library. The funny thing is that if any of the files for
reclamation are still located in the disk storage pool, these take
forever to be copied to the new tape, but if the files come from other
tape volumes, these are copied at a reasonable rate.
Seems that the files on disk should be fast, and the files on tape
slower.
Barry T. Hill
BarryH AT ECHD DOT ORG
> ----------
> From: Pittson, Timothy
> ,HiServ/NA[SMTP:tpittson AT HIMAIL.HCC DOT COM]
> Reply To: ADSM: Dist Stor Manager
> Sent: Friday, July 18, 1997 9:44 AM
> To: ADSM-L AT VM.MARIST DOT EDU
> Subject: Re: Space Rec. of offiste copy pools
>
> 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
> >
>
>
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