ADSM-L

Re: [ADSM-L] Sizing virtual tapes

2007-12-04 22:19:56
Subject: Re: [ADSM-L] Sizing virtual tapes
From: "Schneider, John" <John.Schneider AT MERCY DOT NET>
To: ADSM-L AT VM.MARIST DOT EDU
Date: Thu, 29 Nov 2007 08:55:04 -0600
David,
        Your question is a good one.  On our EMC Disk Libraries we
emulate LTO1 tape drives, with 50GB maximum tapes.  I believe this
improves overall disk utilization for just the reason you mention.  You
can reclaim the smaller tapes sooner.  TSM won't have to wait until
~250GB of data, which may have been written over a period of weeks,
expires before the virtual tape is ready to reclaim.

Best Regards,

John D. Schneider
Lead Systems Administrator - Storage
Sisters of Mercy Health Systems
Email:  John.Schneider AT Mercy DOT net


-----Original Message-----
From: ADSM: Dist Stor Manager [mailto:ADSM-L AT VM.MARIST DOT EDU] On Behalf Of
David E Ehresman
Sent: Thursday, November 29, 2007 8:01 AM
To: ADSM-L AT VM.MARIST DOT EDU
Subject: [ADSM-L] Sizing virtual tapes


How large are you making the max size of your virtual tapes?  Why?

I let my TS7520 emulating 3592E tapes default to a max size of 460GB but
I'm starting to think a smaller size would make more sense.  The median
size of occupancy for my nodes is around 40GB so I'm thinking that might
be a better max size to facilicate reclamination.

David

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