All

Just to chip in here.

We have 3 DDR's (2 at remote sites and one in a main DC)  and are seeing 
4.4:1 compression.  That's with a reasonable mix of data and no client 
side compression.

Whilst dedupe isn't superb, but as we know it's generally lower with TSM 
anyway, a big advantage is DDR to DDR offsite replication for DR.  Our 
nightly backup gets about 10:1 dedupe and is small enough to offsite 
without massive network connectivity.

We also use NFS for TSM connectivity, which seems to work very well.

Steven

Steven Langdale
Global Information Services
EAME SAN/Storage Planning and Implementation
( Phone : +44 (0)1733 584175
( Mob: +44 (0)7876 216782
ü Conference: +44 (0)208 609 7400 Code: 331817
+ Email: steven.langdale AT cat DOT com

 



Nick Laflamme <dplaflamme AT GMAIL DOT COM> 
Sent by: "ADSM: Dist Stor Manager" <ADSM-L AT VM.MARIST DOT EDU>
13/01/2010 01:19
Please respond to
"ADSM: Dist Stor Manager" <ADSM-L AT VM.MARIST DOT EDU>


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Subject
Re: [ADSM-L] DataDomain VTL




Caterpillar: Confidential Green Retain Until: 12/02/2010 



On Jan 12, 2010, at 11:27 AM, Kelly Lipp wrote:

> We have a customer that insisted on buying one of these for his TSM 
environment. Promised 20:1 dedup.  He saw about five to one.  He was in 
our Level 2 class telling the story.  At the end he said he wouldn't buy 
it again.  I made him repeat that part of the story...

DataDomain's "Best Practices" guide for TSM tells customers not to let 
nodes compress data. I have to wonder how much compressing the data or not 
alters the dedup ratio. I'm not at all sure that we're going enforce a "no 
compression" policy for our clients.