ADSM-L

[ADSM-L] Data Domain - questions from a meeting with DD

2009-06-15 09:29:59
Subject: [ADSM-L] Data Domain - questions from a meeting with DD
From: Richard Rhodes <rrhodes AT FIRSTENERGYCORP DOT COM>
To: ADSM-L AT VM.MARIST DOT EDU
Date: Mon, 15 Jun 2009 09:29:08 -0400
Hello,

The other day we had a meeting with Data Domain - just the
normal vendor update about their products.  While informative,
several comments were made by DD systems that I thought I
like your opinions on.  (note:  we are a all tape shop, and
probably will be until the next hardware refresh in several years)

Interesting comments DD made:

1)  de-dup of compressed data.

We told them that much of our backup load comes from Oracle
backups that are already compressed via Unix compress utility
then pushed to TSM.  We asked what effect this would have on
de-dup.  They said we could expect a 4x-5x de-dup ratio on
this compress data.  I had always thought that compressed data
would not de-dup.


2)  NFS mounted storage pools.

They said that the vast majority of their installations,
including TSM installations, use NFS (some OpenStorage for
NetBackup, and a little CIFS) for backups to disk.  In other
words, VTL emulation is a very small percentage of their
installations.  If you have DD hdwr, are you using NFS
or file devices, or, a vtl interface?  Is anyone using NFS
for a storage pool?


3)  DD reclaim of scratch tapes

I asked about when/how DD will reclaim no longer used space.
In other words, when a scratch tape passed reuse-delay.  He
said that DD had some kind of interface to backup softw such
that it knows when data is no longer needed and reclaimes that
space.  I know TSM v5.5 has a feature to clear a vol when no
longer used with a vtl, but DD was saying they had a special
interface to accomplish this.  Does DD have a special interface
to TSM?


Thanks

Rick


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