Walt,

I won't get into details on performance tuning on this list
but I will tell you what some of our customers have seen.
We all know that performance tuning really is rocket science...
...and requires expert analysis.  :-)

We have customers consistently achieving rates greater than
30G per hour when backing up with TDP for Microsoft Exchange.

I do have some comments on your questions.

First TXNGROUPMAX will not make any difference.
TDP for Exchange sends up a maximum of 4 objects for any backup.
All objects for a backup are contained within one transaction.

Second, changing TXNBYTELIMIT won't help either since API applications
(like any of the TDP applications) are not bound to this limit by design.

As far as some of the client options to set...We, by default recommend:

   TCPBuffsize        31
   TCPWindowsize      63

But these may not always be optimal for your environment.

As far as the "/buffers" option.  Our original testing showed that
"/buffers:3,1024" seemed to produce the best results...but again,
these may not always be optimal for your environment.

Thanks,

Del

----------------------------------------------------
Del Hoobler
Del Hoobler
IBM Corporation
hoobler AT us.ibm DOT com


"Fujikawa, Walt" <WFujikaw AT EBMUD DOT COM>@VM.MARIST.EDU> on 09/13/2000 
09:34:04
PM

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:  Exchange tuning



09/05/2000 22:37:09 TcpFlush: Error 10054 sending data on Tcp/Ip socket
268.
09/05/2000 22:37:09 sessRecvVerb: Error -50 from call to 'readRtn'.
09/05/2000 22:37:09 TcpFlush: Error 10054 sending data on Tcp/Ip socket
268.

Getting these errors on my TDP 1.1.1 connect agent for MS Exchange 5.5,
Service Pack 2 on NT Server 4.0, Service Pack 4.  Tivoli Server is 3.7.3.6
on NT Server 4.0, Service Pack 6a.

Backup times seem slow.  18 mins to back up a 1.5gb info store.  Servers
are
on a CAT5000 switch with ports set at full duplex/100mb.  NICS are set to
full duplex/100mb.  Servers are on the same segment.

Will upping the TXNBYTELIMIT help?  Can setting too high corrupt your IS?

What about the:

TCPBUFFSIZE?
TCPWINDOWSIZE?
TXNGROUPMAX?  How does TDP determine commit points on a large Information
Store?
SELFTUNETXNSIZE?  Why is this turned off by default?


On the "excdsmc" command line I am going to experiment with /buffers:
parameter.  Has anyone out there messed with these settings with favorable
results.  The alternative is to call Consultline which I understand is
chargeable.  I may have to stay with Veritas instead of converting other
Exchange servers to Tivoli.


Walt Fujikawa
East Bay Water Systems Programming
Wfujikaw AT ebmud DOT com <mailto:Wfujikaw AT ebmud DOT com>