RE: Using OS/400 AutoTuner -- MIDRANGE-L

That's what I have been doing ...

thanx

Kenneth

-----Original Message-----
From: Raikov, Lo [mailto:RaikovL@mki.com.au]
Sent: Monday, May 22, 2000 8:42 PM
To: Graap, Ken
Subject: RE: Using OS/400 AutoTuner


 Ken

run WRKSHRPOOL command and press PF11 for the pool tuning characteristics.
Check the minimum values for the *BASE and *MACHINE pools. You have a lot of
main storage. Try to increase the minimum values, especially if they are
around 100-200Mb each, as it may very well be the case. 

Lo

-----Original Message-----
From: Graap, Ken
To: 'Midrange'
Sent: 5/23/00 4:33 AM
Subject: Using OS/400 AutoTuner

We have one system supporting, production and development.

It is difficult to determine what kind of work will be submitted or run
interactively at any particular time.

In order to insure optimum memory allocation between storage pools, I am
using the OS/400 AutoTuner (QPFRADJ=3).

We have 16GB of RAM on our Model 730 and are at V4R4.

During the day I see as high as 10GB memory allocations between pools,
usually *Shrpool1 AND *Interact...

The pools are defined as follows:

                                                                 
              Defined    Max   Allocated   Pool  -Paging Option--
Pool         Size (M)  Active  Size (M)     ID   Defined  Current

*MACHINE       895.17   +++++      895.17    1   *FIXED   *FIXED 
*BASE         1638.40      72     1638.40    2   *CALC    *CALC  
*INTERACT     7807.52      30     7807.52    4   *CALC    *CALC  
*SPOOL          81.91      15       81.91    5   *FIXED   *FIXED 
*SHRPOOL1     5960.98      15     5960.98    3   *CALC    *CALC  

Batch work runs in SHRPOOL1.

I'm currently trying to figure out why we are experiencing periodic
system
slowdowns even though our CPU utilization averages less than 20%, disk
arm
utilization around 5% and faulting around 10-20 per second in *INTERACT
and
*SHRPOOL, most of that being DB Faulting.

I'm able to control the memory allocation swings somewhat using the
WRKSHRPOOL command interface:

                       -----Size %-----  -----Faults/Second------ 
 Pool        Priority  Minimum  Maximum  Minimum  Thread  Maximum 
 *MACHINE         1      5.48      100     4.00     .00     6.00  
 *BASE            2     10.00    85.00    10.00    2.00      100  
 *INTERACT        2     25.00    85.00     5.00     .50      200  
 *SPOOL           4       .50     3.00     5.00    1.00      100  
 *SHRPOOL1        3     10.00    85.00    10.00    2.00      100  

I change the Minimum values to control how much storage is available to
reallocate....

I would prefer not to restrict memory allocation too much, because it
can
result in substantial amounts of memory being left in a pool that isn't
being used. I would like to give the OS/400 tuning algorithm as much
control
as possible over tuning, as long as it doesn't prove to be detrimental
to
interactive response times or batch throughput.

I would suspect that large (10GB or more) memory reallocation might
result
in some slowdown for interactive users as pages originally resident in
RAM
are being written to disk, but could this be causing my system to slow
down
significantly?

Any thoughts or comments are welcome. I'm just exploring
possibilities...


Kenneth

****************************************
Kenneth E. Graap
IBM Certified Specialist
AS/400 Professional
Network Administrator
NW Natural (Gas Services)
keg@nwnatural.com
Phone: 503-226-4211 x5537
FAX:    603-849-0591
****************************************


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