On 12/27/2012 12:51 PM, Billaudeau, Pierre wrote:

I noticed a serious performance drop when our backup primary tapes to copypool runs at 
night (VTL Quantum DXi8500 to TS1140 tapes). The throughput of backups to VTL drops when 
the DXi "rehydrates" the deduplicated/compressed virtual tapes. I can imagine 
the reclamation process does the same thing. There is a need to adjust maintanance 
schedules to avoid the situation.

Pierre Billaudeau
Analyste en stockage
Livraison des Infrastructures Serveurs
Société des Alcools du Québec
514-254-6000 x 6559

-----Message d'origine-----
De : ADSM: Dist Stor Manager [mailto:ADSM-L AT VM.MARIST DOT EDU] De la part de 
Schneider, Jim
Envoyé : 27 décembre 2012 11:18
À : ADSM-L AT VM.MARIST DOT EDU
Objet : Re: [ADSM-L] Reclamation of Virtual Tapes

Our primary (and only) storage is a Data Domain.  Be careful when reclaiming 
virtual tapes.  It works perfectly but servers backing up to the Data Domain 
have their bandwidth throughput drop from 85% to 5% during reclamation.  This 
was determined by watching Windows Task Manager network utilization with 
reclamation running and then cancelled.

Our reclamation threshold is set at 95% and runs for about 20 minutes.  The SQL 
storage pool that holds 1.1 TB files is set at 99% to effectively prevent 
reclamation.  We had a bad weekend where reclamation started Friday at 5 PM and 
was 60% complete Monday morning before being cancelled.  All of those weekend 
backups were slowed and the database backup ran 5 hours instead of 1.75 hours.

Don't make my mistakes!

Jim Schneider

-----Original Message-----
From: ADSM: Dist Stor Manager [mailto:ADSM-L AT VM.MARIST DOT EDU] On Behalf Of 
Ehresman,David E.
Sent: Tuesday, December 18, 2012 2:38 PM
To: ADSM-L AT VM.MARIST DOT EDU
Subject: Re: [ADSM-L] Reclamation of Virtual Tapes

We reclaim our virtual tapes.  They have the same waste patterns as physical 
tape and are certainly as expensive.

David

-----Original Message-----
From: ADSM: Dist Stor Manager [mailto:ADSM-L AT VM.MARIST DOT EDU] On Behalf Of 
Lee, Gary
Sent: Tuesday, December 18, 2012 2:10 PM
To: ADSM-L AT VM.MARIST DOT EDU
Subject: Re: [ADSM-L] Reclamation of Virtual Tapes

Sounds like someone set the reclaim storage pool on the virtual tape pool to 
the physical tape pool.

I know of no reason why not to reclaim virtual tapes.

Wish I had one to play with.


Gary Lee
Senior System Programmer
Ball State University
phone: 765-285-1310



-----Original Message-----
From: ADSM: Dist Stor Manager [mailto:ADSM-L AT VM.MARIST DOT EDU] On Behalf Of 
Welton, Charles
Sent: Tuesday, December 18, 2012 11:10 AM
To: ADSM-L AT VM.MARIST DOT EDU
Subject: [ADSM-L] Reclamation of Virtual Tapes

Hello:

We have a TSM instance that uses virtual tapes as our primary backup data pool. 
 The data on the virtual tapes are eventually migrated to tape.  We are 
currently down to 3 virtual scratch tapes and 6 physical scratch tapes.  I 
noticed that we are not running any reclamation processes on our virtual tape 
pool.  It seems we have a hand-full of under-utilized virtual tapes.  I went 
ahead and ran a manual reclamation on the virtual tape pool and I noticed the 
output tape pool is a physical tape.  I assumed that the virtual tape would 
reclaim to another virtual tape.  Is that not the case?

Could there be a reason why reclamation shouldn't be ran on a virtual tape pool?

Thank you...


Charles

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