RE: Balancing Disk Data Across Arms

["Law, Tom" <actlaw@xxxxxxxx>]

                Please ignore the following message.  Our server had a
problem and resent messages back over the internet.

                I received several good responses to the original
message.  Thanks for the feedback.


                Tom


                ORIGINAL MESSAGE:
                Has anyone used the DSKBAL command provided by IBM on a
4.2 system?  This function is available via PTF.

                We run some accounting Monthend jobs that are heavy I/O.
When these jobs run, other batch jobs slow down (other batch jobs are
actively running) and show I/O waits in  Performance Tools.

                In the past year, we have added several disk drives to
this system.  Generally, 1 or 2 at a time.  I believe what has happened
is that since these drives are empty when they are added, the IBM
algorithm for spreading data across arms actually fills these empty
drives until the percentage used is even again across all arms.  Thus,
restoring or copying files in production applications actually put this
data on  these empty drives.  (timing)    I can see in performance tools
that during the Monthend process, 4 or 5 arms will exceed the guidelines
for the device.  These are the where the accounting data is located.

                Without doing a full SAVSYS and RESTORE (option 21),
The Support Center told me to install this PTF and use the DSKBAL
command.  

                Any help would be greatly appreciated.

                Thanks    
                        
                Tom
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