Re: Tuning tips?

1997-12-10 12:16:29
Subject: Re: Tuning tips?
From: Lee Russon <lee.russon AT MEB.CO DOT UK>
Date: Wed, 10 Dec 1997 12:16:29 -0500

Consider using ADSM compression on your AIX clients as this can improve network 
throughput. We tested RS/6000 AIX clients running with compression and without 
and found that the backup of data took 3 times as long without compression. If 
network bandwidth is not a problem then leave compression off, but remember 
that more data will be processed by the server before the data arrives on tape.

We transfer all client backup data to a primary disk pool overnight and copy 
the disk pool data to tape after all clients have been backed up. The tapes are 
then sent to off-site storage. During the day we migrate data from the disk 
pool to on-site tape to free up space for the next nights run. This method 
seems to work quite well as client machines do not have to wait for tapes to be 
mounted and the server has less data to process.

The options you use on the clients are very similar to our own, but you may 
find that increasing the TXNBytelimit may improve performance (it all depends 
on how fast your HP/IBM machines are)

Lee Russon
Midlands Electricity plc
From: McGrew, Perry
To: adsm-l AT vm.marist DOT edu
Subject: Tuning tips?
Date: 10 December 1997 13:59

We've just installed ADSM/MVS 3.1 on our TCP/IP 3.2 Ethernet network
over ATM (LANE) backbone.  We have the lastest ADSM 3.x client code on
our HP-UX 10.2 & IBM AIX 4.3 servers.
In the dsmsched.log I am seeing:
Network data transfer rate:        1,772.97 KB/sec
Aggregate data transfer rate:      1,468.25 KB/sec
We do not have ADSM compression turned on as we are using hardware
compression on our 3494/3590 MagStar tape drives.
Our TCPIP/MVS 3.2, the  LARGEDATABUFFERPOOLSIZE is set to 32768.
In the HP / AIX Clients' the dsm.sys parameters are:
   TCPWindowsize      64
   TCPBuffsize             32
   TXNBytelimit       2048
Any help in identifying critical tuning points will be appreciated!
Perry McGrew
Agway Inc.
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