Charles,

The one thing to be aware of with any dedupe offering is that when using
a dedupe system with TSM, you will get significantly smaller dedupe
ratios than those customers using it with Grandfather-father-son-based
software (e.g. NBU, NW, CV) due to the progressive incremental nature of
TSM.  Where a lot of the dedupe comes from is reducing the redundancy
caused by creating repeated full backups.  Since TSM doesn't create
repeated full backups on filesystems, they don't get as much dedupe.
Depending on the product, I've seen everything from 3:1 to 10:1.  If
it's 3:1, that's a joke, as you can get almost the same with just
hardware compression, which costs far less.

Also, all dedupe products are not created the same, and this is
especially true for TSM.  So if you hear FUD about particularly bad
dedupe rates from someone, don't assume that all vendors would get that
dedupe ratio, or even that you would get that dedupe ratio with that
vendor.  Make sure to ask your vendor about their knowledge of TSM
configs with their product.

Here are a few resources that may help in your search.

First, here is a link to the discussion on this list that someone eluded
to.  (44 posts on deduplication with TSM):
http://tinyurl.com/3bwc9a

BackupCentral.com has a Wiki that contains a directory of all disk
targets for backups:
http://tinyurl.com/2dtvh2

This is the first entry in a multi-part series on deduplication.  Each
blog entry contains a link to the next entry in the series:
http://www.backupcentral.com/content/view/58/47/

This is a podcast I did on dedupe:
http://searchstorage.bitpipe.com/data/document.do?res_id=1188480907_629

Hope this helps!

---
W. Curtis Preston
Backup Blog @ www.backupcentral.com
VP Data Protection, GlassHouse Technologies 

-----Original Message-----
From: ADSM: Dist Stor Manager [mailto:ADSM-L AT VM.MARIST DOT EDU] On Behalf Of
Lamb, Charles P.
Sent: Wednesday, December 12, 2007 10:19 AM
To: ADSM-L AT VM.MARIST DOT EDU
Subject: [ADSM-L] Data Domain Question

Hi....

We are an IBM shop.  We were wondering if anyone is using data domain
material with their TSM system??  We were wonder about interoperability
and any operational concerns with adding a 3rd party product into our
IBM shop which could cause any problems??  Thoughts??

PS -- We do not have any VTLs.  We have a large RISC TSM server with a
large IBM 3584-L32/D32s library using LTOs with IBM DR product.