Your backup sizing is quite small;  are you sure it's that small?  There are
Redbooks on sizing for AIX;  also, there is much material from SHARE
proceedings on performance and tuning.

A more typical arrangement (I've seen) for a single-client+server situation
might be 50 GB to start, up to 100 GB total backup occupancy, on a
file/print server that is also a TSM server (and client) -- which I had at
two sites;  we configured with 4-way Dell processors, 512MB RAM, external
RAID for the file-served data, internal drives for the TSM db, log & disk
pool (102 GB).  This was a software development & marketing site, this HW
config was more than sufficient to handle both TSM and file-server loads
with sub-second response time for normal business day users... the main
deficiency was only one tape drive, so we insisted that primary storage
pool )for backups) stay on disk, two copy pools to tape (one for onsite, one
for offsite) to fully protect their data -- which we limited to 60 GB of
file server storage.

Don France
Technical Architect - Tivoli Certified Consultant
Professional Association of Contract Employees (P.A.C.E.)
San Jose, CA
(408) 257-3037
don_france AT att DOT net