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Former Member
Jun 27, 2008 at 01:47 AM

Performance tuning for OS400 - three instances

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I have an OS400 LPAR that has been setup with 10GB RAM and 40GB swap space.

The LPAR supports three SAP systems, a development ERP, QA ERP and PI Development system (ABAP+JAVA). All systems are based from the Netweaver 7.0 stack.

Quite often the CPU maxes at 100% of utilization. This occurs even when the DB02 transaction is started and CPU will hit 100% for approximately 30 seconds (the time for DB02 to load is about 35 seconds).

Work with System Status SAPDEV

27/06/08 11:10:56

% CPU used . . . . . . . : 100.0 System ASP . . . . . . . : 846.7 G

% DB capability . . . . : 26.3 % system ASP used . . . : 86.3558

Elapsed time . . . . . . : 00:00:01 Total aux stg . . . . . : 846.7 G

Jobs in system . . . . . : 6277 Current unprotect used . : 34170 M

% perm addresses . . . . : .010 Maximum unprotect . . . : 39988 M

% temp addresses . . . . : .117

Sys Pool Reserved Max -


DB----- Non-DB - Act- Wait- Act-

Pool Size M Size M Act Fault Pages Fault Pages Wait Inel Inel

1 700.00 244.04 +++++ .0 .0 .0 .0 188.4 .0 .0

2 10008.06 6.70 3000 1.8 28.8 1.2 2.5 2713 .0 .0

3 400.00 .07 151 .0 .0 .0 .0 37.6 .0 .0

4 80.00 .00 5 .0 .0 .0 .0 .0 .0 .0

The wrkdsksts occassionally hits 100% busy, but most of the time, averages:

Work with Disk Status SAPDEV

27/06/08 11:39:01

Elapsed time: 00:00:53

Size % I/O Request Read Write Read Write %

Unit Type (M) Used Rqs Size (K) Rqs Rqs (K) (K) Busy

1 4328 105847 82.2 44.2 9.6 30.1 14.0 6.1 17.3 3

2 4328 105847 88.9 4.2 15.1 1.5 2.7 29.2 7.4 1

3 4328 105847 89.0 4.9 13.5 1.7 3.1 23.4 7.9 1

4 4328 105847 88.8 5.1 15.6 2.2 2.8 24.7 8.5 1

5 4328 141129 85.4 6.5 14.3 2.8 3.6 22.4 7.9 2

6 4328 141129 85.4 5.8 16.5 2.6 3.2 28.1 6.9 2

7 4328 141129 85.4 6.1 16.6 2.6 3.4 28.8 7.2 1

Does this appear to be a CPU related limitation for performance or am I able to better tune the memory/disk allocation?

Quite often the Java stack on the PI system seems to hang and needs to be restarted.

Would it be useful for me to split the memory in multiple pools to support ERP and the PI systems separately?

Thanks for your assistance!