Have you tested what is the performance of FAStT 500 disks? Those were 
mid-class disk storage originally designed for PC servers market and later 
modified to be compatible with rs6k/pSeries.
Try some simple tests on the TSM server when quiet:
'date; dd if=/dev/zero of=/fastt_fs/test_file bs=262144 count=16384; 
date' to test write speed. Use large file to simulate TSM heavy load.
'date; dd if=/fastt_fs/test_file of=/dev/null' to check read speed
Also check your Gb Ether - are you using Jumbo frames, have you enabled in 
AIX 'no -o rfc1323=1', what are send&receive bufsizes, what is 
TCPWindowsize of TSM server&client. Have you measured LAN&disk load during 
backup?

Zlatko Krastev
IT Consultant



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Subject:        Tuning TSM

Hi:
I'm managing a pretty small TSM installation with 4 RS/6K machines (2
6M1 and 2 6H1) running AIX 4.3.3 (ML9).
TSM software consists of the server (running in a 6M1 - 7Gb RAM), and
the clients running in the same machine and on the others.

I´ve got the following situation:
the total of data backed up is about 200Gb's,
4 servers are connected using gigabit ethernet links (and have 6Gb RAM
and 7Gb RAM each model 6H1 and 6M1 respectively)
TSM uses a storage pool of 240Gb on FastT500 disks (those are
connected by FC channels)
TSM uses a 3581 library (LTO) with 1 drive,

The fact is (for the same set of information):
When I do an archive backup operation with TSM, the time elapsed rounds
5 hours (TSM writes "right to" the tape).
When I do an incremental backup operation, TSM uses about 6:30hs for it
(TSM writes to storage pool).

I'm looking for a rational approach to solve this "problem": isn't it
more fast writing to storage pool (disk) that to tape?

Anyone had the same performance problem?

Is it really a performance problem?

I would like some commentaries about this, I can provide some info about
the configuration of TSM and the AIX servers.

Regards

Ignacio