ADSM-L

Re: Archive performance problem from TSM Server itself

2005-04-13 17:37:11
Subject: Re: Archive performance problem from TSM Server itself
From: Eric Winters <ewinters AT AU1.IBM DOT COM>
To: ADSM-L AT VM.MARIST DOT EDU
Date: Thu, 14 Apr 2005 07:36:49 +1000
Dave,

Thanks for the suggestion - vmtune settings are the same on both the TSM
Server and the networked server.
It appears our problem is likely to be due to 'what' we are trying to
backup - it's a locally mounted flashcopy. However the data is apparently a
'no copy flashcopy', which means that the data isn't really there at all,
but is built on the fly by reading data from the source luns. It is almost
certainly this overhead which is slowing things up - our networked server
backed up the original true files and hence enjoyed better performance.

Thanks to all for input.

Regards,

Eric Winters

IBM Storage Group
F21, 55 Coonara Av. Cumberland Forest NSW 2125
Ph: +61-417 460 283 (mobile)
     : +61-2-9354 4789 (voicemail)




You may also want to look at your VMM options. Can you cut and paste the
output from a vmtune -a command to this post? (Or ioo and voo, whichever
you want).


At 04:54 PM 4/12/2005 +1000, you wrote:
>Dear All,
>
>TSM Server 5.2.4 on AIX 5.2 with 6 GB memory. (p690 lpar)
>3592 tape drives fibre attached.
>TSM Backup/Archive client 5.2
>
>I have a large number of 2 GB files to archive directly to tape - the
files
>are within filesystems on a SAN storage device. If I mount the filesystems
>locally on my TSM Server and archive them, I get a rather disappointing 22
>MB/s when archiving to a single tape drive.
>
>If I archive the same data in the same filesystems but by mounting them
>onto a remote AIX server and running the 'dsmc archive' command and send
>them over the Gb lan, then I get a far more satisfactory 37 MB/s (again,
>archiving to a single tape drive).
>
>Why should performance archiving over the network be better than archiving
>locally? My remote server is similarly configured to my TSM Server - same
>version of AIX, backup/archive client, similar memory etc.
>
>I have tried using SHAREDMEM but it made no difference. Also tried raising
>the TCPW from 64 to 128, no difference. Tried a TCPBuffsize of 512 instead
>of 32, no difference.
>
>Indeed my client options are the same on both the TSM Server and the
remote
>server.
>
>Any suggestions gratefully received.
>
>Server Options
>=============
>BufPoolSize             512288
>TCPW                        64
>TCPNODELAY       YES
>TXNGROUPMAX   256
>
>Client Options
>============
>COMMmethod        TCPip
>Compression          No
>TXNBYTELIMIT     2097152
>TCPBUFFSIZE        32
>tcpwindowsize        64
>TCPNODELAY      Yes
>
>
>Regards,
>
>Eric Winters
>Australia

Dave Canan
TSM Performance
IBM Advanced Technical Support
ddcanan AT us.ibm DOT com

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