SAP on IBMi Power7 770 Performance Problem

[Former Member]

     I know this is a vague question, but we are implementing SAP on a IBMi 770 w/ 32 processors and we are having tremedious performance problems. We are in our last test cycle and things just don't add up. I have basis folks from our cloud provider saying they have never seen an installation of SAp on such a large set of IBMi iron, but yet we suffer. I'm looking for any suugestions of how to move mointains here. Why is it so hard to find the correct person(s) to tackle this issue? It's would seem to me IBM would go out of it's way to make the iBMi the prefered ERP platform of choice?    

[rdiger_hckel]

Hello,

the tradiditional memory management may be the reason for this (I know a customer who migrated to a 795 with more than 70 cores and experienced many problems as well).

The profile parameter ES/TABLE = SHM_SEGS may be a solution, please read SAP Note 808607 - iSeries: Memory management in a system based on PASE

for more information.

Prerequisites:

* IBM i 6.1, 6.1.1 or 7.1

* downwardcompatible kernel 7.20 or 7.20 EXT (patch level #220 or higher)

* new user concept (see SAP note 1149318) -> tool CONVUSRCPT

Also make sure to have the latest PTFs and kernel patches installed.

I think someone from IBM can confirm this.

Hope this helps,

Rüdiger Höckel

apetito AG

SAP Basis Admin

[christian_bartels]

Hi Todd and Rüdiger,

as a member of the SAP on IBM i porting team I can confirm Rüdiger's answer. Switching the memory management to ES/TABLE=SHM_SEGS has helped for at least two customers with large machines using Power7.

Unfortunately there is no easy way to verify that it will help. To be sure, you would have to take a PEX trace (TPROF). If hypervisor calls are responsible for a significant percentage of CPU utilization, changing the memory model will help. The IBM support can help you setting up and analyzing the PEX trace.

Kind regards,

Christian Bartels.