That sounds about right.  Data Domain's a good product with a lot of
happy customers, but TSM customers who are only backing up files and
only keeping 3 versions aren't going to be among them. ;)  You've got to
backup database/app/email type data that does recurring full backups
and/or keep a whole lot more than 3 versions to have de-dupe make sense
for you.  That's not a Data Domain thing.  That's just how de-dupe
works.

In addition, it won't work if you use it as you would normally use a
disk pool (1-2 days of backups and then move to tape).  There won't be
anything to de-dupe against, and you'll get close to nothing.  You need
to leave your onsite backups permanently on it for de-dupe to work.

---
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
Dirk Kastens
Sent: Tuesday, August 28, 2007 9:18 AM
To: ADSM-L AT VM.MARIST DOT EDU
Subject: Re: [ADSM-L] Data Deduplication

Hi,

Jon Evans wrote:
> Dirk
>
> I also tried Data Domain and was not impressed. I now use Diligent's
> Protectier and its far more impressive. Its scalable, reasonably
priced,
> achieves throughput of 200mb per second and better and factoring
ratio's
> of
> Over 10 to 1

We mainly backup normal files and only use 3 backup versions so that the
compression will not be more than 3:1 or 5:1. The best results can be
achieved with databases and application data like Exchange. That's what
the people from DataDomain said. I'm just running another test with
MySQL and Domino data. Let's wait and see :-)

--
Regards,

Dirk Kastens
Universitaet Osnabrueck, Rechenzentrum (Computer Center)
Albrechtstr. 28, 49069 Osnabrueck, Germany
Tel.: +49-541-969-2347, FAX: -2470