In the "best practices" document from DataDomain
http://www.datadomain.com/pdf/GlassHouse-TSM-DataDomain-Whitepaper.pdf
and what other things I read, it sounded like the VTL "mimicry" is not
really needed in a TSM environment unless you are doing lan-free or NDMP
backups. This shop does neither, so there was no need to buy the VTL
option. I just made deviceclasses and storagepools and slipped it into
the storage pool hierarchy.

You are also dead on for the analysis. They recommend that you create
storagepools for the various types of data to keep track of what kind of
compression you are getting. In our case, it was "databases",
"fileservers" and "archives". Our installer said some folks go much more
granular, even as far a 1 storagepool per host, but I didn't want to
create a nightmare in storagepools, so I kept it simple. 

 Each storage pool on the TSM server points to a different directory on
the DataDomain appliance, and the appliance can tell you what the
compression rates are: overall, for each filesystem on the appliance,
and even for each "FILE" the TSM server creates. With that data and a
drill-down using the "q content" command you can pick out the
uncooperative data.

Ben
 

-----Original Message-----
From: ADSM: Dist Stor Manager [mailto:ADSM-L AT VM.MARIST DOT EDU] On Behalf Of
Paul Zarnowski
Sent: Tuesday, February 26, 2008 4:04 PM
To: ADSM-L AT VM.MARIST DOT EDU
Subject: Re: [ADSM-L] TSM dream setup

Ben,
First, thanks for sharing your experiences.  Very enlightening.

I'm curious why you decided to use devclass=file volumes, instead of
using the DD580 as a VTL.  It does have a VTL personality, doesn't it?

At 05:39 PM 2/26/2008, Ben Bullock wrote:
>TSM config - Easy. Created some "FILE" device classes and pointed them 
>to the NFS mount points.


You also did some analysis about what type of data got what level of
reduction.  How did you go about testing this?  Do you use separate
storage pools to segregate the data and then run a test?  I don't see
any other way to do it.

Thanks.
..Paul



--
Paul Zarnowski                            Ph: 607-255-4757
Manager, Storage Services                 Fx: 607-255-8521
719 Rhodes Hall, Ithaca, NY 14853-3801    Em: psz1 AT cornell DOT edu

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