ADSM-L

Re: Tuning TSM

2002-05-16 07:22:49
Subject: Re: Tuning TSM
From: Ignacio Vidal <ividal AT BIYCSA.COM DOT AR>
Date: Thu, 16 May 2002 08:21:53 -0300
Zlatko:
Here are the answers:

> 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.

This is completely true: IBM installed FastT500 instead of  SSA disks
(they said they were faster).
We have done a "re-cabling" of these devices, and got a better IO
balance on the controllers.

> 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

In a test like you proposed, FastT500 brings a peformance of about
60MB/sec

> 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?

Yes, we're using this parameters:
<from "no">
                tcp_sendspace = 1048576
            tcp_recvspace = 1048576
            udp_sendspace = 64000
            udp_recvspace = 64000
                rfc1323 = 1
                
<from TSM server>
TCPWindowsize         1310720

What I've observed is that during a client backup session, TSM seems to
be idled for a long time (and the server machine has not constraint
problems for memory or I/O)

I can send other data.
Thank you all.

Ignacio







> 
> Zlatko Krastev
> IT Consultant
> 
> 
> 
> Please respond to "ADSM: Dist Stor Manager" <ADSM-L AT VM.MARIST DOT EDU>
> Sent by:        "ADSM: Dist Stor Manager" <ADSM-L AT VM.MARIST DOT EDU>
> To:     ADSM-L AT VM.MARIST DOT EDU
> cc: 
> 
> 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
> 
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