ADSM-L

Re: [ADSM-L] VTL and TSM - Hyper Reclamation ????

2008-06-04 13:02:28
Subject: Re: [ADSM-L] VTL and TSM - Hyper Reclamation ????
From: Kelly Lipp <lipp AT STORSERVER DOT COM>
To: ADSM-L AT VM.MARIST DOT EDU
Date: Wed, 4 Jun 2008 11:01:15 -0600
I'm with Wanda on this: reclaim aggressively on file device class stuff.  Might 
as well have as much space available as possible. We set up our disk based 
STORServers with reclamation thresholds of 20%. Heck, the system sits doing 
nothing a lot anyway might as well have it moving bits around.  Besides, you 
want to keep those cheap SATA drives spinning don't you?  Three year warranty: 
burn up within three years!

OK, so that's not that funny.

Kelly Lipp
CTO
STORServer, Inc.
485-B Elkton Drive
Colorado Springs, CO 80907
719-266-8777
www.storserver.com


-----Original Message-----
From: ADSM: Dist Stor Manager [mailto:ADSM-L AT VM.MARIST DOT EDU] On Behalf Of 
Richard Rhodes
Sent: Tuesday, June 03, 2008 7:08 PM
To: ADSM-L AT VM.MARIST DOT EDU
Subject: [ADSM-L] VTL and TSM - Hyper Reclamation ????

We are investigating VTL's as a replacement for our 3494 libraries.
A vendor was describing their sizing calculations and
assumptions.  One of their assumptions BLEW US AWAY!!  The
vendor recommended that reclamation  be done
on VTL volumes at a 20-30% Reclamation Percentage.  YES,
that's right, they recommend that a volume get reclaimed
when only 20-30% of the data is expired.  They claim that
this is possible due to the efficiencies and speed
of the VTL, and thus allow us to run at a much higher
average utilization.  The argument is that with a
higher average utilization we can purchase less disk, and
thus a less expensive VTL.

Currently, for our tapes, we reclaim at 55-60%.

Q)  Has anyone every heard of performing
reclamation at a percentage as low as 20-30%?

Q)  Is anyone with a VTL actually performing
reclamation at 20-30%?

Thanks!

Rick


-----------------------------------------
The information contained in this message is intended only for the
personal and confidential use of the recipient(s) named above. If
the reader of this message is not the intended recipient or an
agent responsible for delivering it to the intended recipient, you
are hereby notified that you have received this document in error
and that any review, dissemination, distribution, or copying of
this message is strictly prohibited. If you have received this
communication in error, please notify us immediately, and delete
the original message.