Using sequential-access File volumes with TSM seems to result in a lot of
file level fragmentation.  We are doing a mini-pilot with 25GB File volumes
for the storage pool volumes for some nodes.  These volumes end up very
fragmented (some of the files are in 9000 fragments).

This could have performance implications.

Tivoli may be looking at this for futures?

A VTL may address this.

I did a quick restore test of a node as follows:

36 GB restored
219,170 objects

On fragmented File Volumes:
Time 34.6 minutes
17.7 MB/sec

After defragmenting the file Volumes:
Time 21.9 minutes
27.9 MB/sec

It was not a controlled test as it was run on a production server so there
could have been other things affecting the two tests.

TSM Server 5.2.2.4 on Windows 2003
TSM Client 5.2.2.9 on Windows 2003

Tim Rushforth
City of Winnipeg
-----Original Message-----
From: Tab Trepagnier [mailto:Tab.Trepagnier AT LAITRAM DOT COM]
Sent: June 16, 2004 8:48 AM
To: ADSM-L AT VM.MARIST DOT EDU
Subject: Re: Tier'ed library

Milton,

Thanks for the info.  I briefly looked at Sepaton, but I had no idea they
were that inexpensive.  I will probably give them a second look.

But one thing that I'm struggling with is "why a VTL?"

Between random-access DISK volumes and sequential-access FILE volumes what
does a VTL buy me that I couldn't implement using those two volume types
in TSM?

Thanks.

Tab Trepagnier
TSM Administrator
Laitram, L.L.C.