What are your throughput values?  Tape is not necessarily slower than
disk, especially when the data is compressed on the tape drive.

Orville L. Lantto
Datatrend Technologies, Inc.  (http://www.datatrend.com)
IBM Premier Business Partner
121 Cheshire Lane, Suite 700
Minnetonka, MN 55305
Email: Orville.Lantto AT datatrend DOT com





Steve Freeman <sfreeman AT ACRLIMITED.CO DOT UK>
Sent by: "ADSM: Dist Stor Manager" <ADSM-L AT VM.MARIST DOT EDU>
07/24/02 11:00 AM
Please respond to "ADSM: Dist Stor Manager"


        To:     ADSM-L AT VM.MARIST DOT EDU
        cc:
        Subject:        diskpool performance


Please could someone advise me on the following issue we have with tsm.
I am a TSM novice and would appreciate some pointers etc.

Environment :  TSM 4.2.0  AIX4.3.3 ML09 Server and Client on same Server
using Sharedmem

2 Stgpools defined diskpool and tapepool

we have created a diskpool on RAID5 and created random access volumes
Total Diskpool size is 150GB. Our nextpool is tapepool for migration
upon high thresholds being reached.

We have compression turned off on the client  and set the selftune
parameters in dsmserv.sys
SELFTUNEBUF
SELFTUNETXN


Issue:  IF we initiate a client backup using sharedmem to the diskpool,
it seems to take the same time as it does to backup the client straight
to tapepool. I would have thought the diskpool access
would be quicker ?

The Diskpool is located on direct fibre attached storage with large
read/write cache. The tapepool
is SCSI attached ATL library with 2 drives

Any suggestions or pointers to increase the throughput to a respectable
level would be appreciated.

kind regards
steve freeman
sfreeman AT acrlimited.co DOT uk