How are you using it?  As your disk cache?  You have to store backups on
it long term in order to get de-duplication.

---
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: Monday, August 27, 2007 12:31 AM
To: ADSM-L AT VM.MARIST DOT EDU
Subject: Re: [ADSM-L] Data Deduplication

Hi,

> Writing a de-dupe backup product isn't easy.  EMC bought Avamar and
> Symantec bought Data Center Technologies to get their respective
> products. I don't know of any other de-dupe companies for IBM to
> acquire, so they'll have to write their own.  That may take them a bit
> longer.

We're just testing a deduplication disk array from DataDomain with TSM.
The compression ratio is much less than promised by the sales people.
During the last 10 days of incremental backups we only achieved a ratio
of 2.6:1. The disk array is very expensive and for the money you can buy
more disks than you need without compression.

--
Regards,

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