We started out with 4GB volumes and have moved to 10GB volumes.  Both
have worked fine - we predefine them on Windows 2003 - TSM 5.3 so that
the volumes do not become fragmented at the OS level.

We currently have a size limit on this pool so that "large" files are
still stored on tape. (Our current "large" value is 2GB and really
depends on how much disk we have.)

We are also trying out Exchange backups on a devtype=file pool and have
used 100GB volumes for this.

We are currently not collocating.  My original thoughts were that
multi-session restore would perform better with no collocation and some
original testing I did with this showed these results.  

See the "Understanding Disk Storage in TSM" at
http://tsm-symposium.oucs.ox.ac.uk/contributions.html for some good info
on collocation and volume sizes.  This suggests that you might want to
collocate (at least at some level).

FYI - I just did a multi-session restore test of a Windows 2003 file
server with data on the above 10GB file pool with the following results:
# of Objects - 164,674
Aggregate KB - 41,083
Elapsed time - 00:20:28

This data was actually compressed, the source being 58.3 GB (so the
actual throughput is 49,781 KB/sec).  In this case the client CPU was
probably the bottleneck.


Tim Rushforth
City of Winnipeg
  

-----Original Message-----
From: ADSM: Dist Stor Manager [mailto:ADSM-L AT VM.MARIST DOT EDU] On Behalf Of
Spearman, Wayne
Sent: Monday, December 05, 2005 3:34 PM
To: ADSM-L AT VM.MARIST DOT EDU
Subject: [ADSM-L] Disk Only backups

We are planning to move a large number of our nodes to "disk only"
backups and eliminate tape for them. The diskpools will be devtype=file.
I struggle with whether to collocate these disk volumes or not and how
large to make them. I've had some discussions with IBM, but would like
to ask others to share their experiences with me.

Any input would be welcome.

Thanks,
Wayne




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