System performance deteriorated after Upgrading to V6R1

[Former Member]

Dear Experts

we had upgraded our SAP ECC and XI machines to V6R1. We were expecting a performance improvement after the upgrades. But unfortunately the system performance is very bad. As per the note 1264859 we could understand that there will be deterioration in performance after upgrade due to database statistics update. We have upgraded the machine on 15th of April and till now we are not observing any improvement in performance. Rather it deteriorated from the state when it was running with V5R4. We had passed through a terrible month end, where even after providing additional resources system was touching 98 % in CPU and disk as well. One more observation is once after we restart the application servers, the central instance CPU and disk utilization will be normal for 2 days and on the third day again it starts going high. We had upgraded the latest kernel before carrying out the V6R1 upgrade as well as we had updated the latest DBSL in all application servers. We had converted to XDN driverless connectivity with the following instance parameters in all application servers.

dbs/db4/dbsl_buffer_size 524288

dbs/db4/da_cache_size 100

Need expert advice to sort this performance issue.

[christian_bartels]

If you see high CPU utilization and the performance deteriorates over time after an IPL, you may want to check PTF SI45959 for APAR SE50953. It fixes a problem that was recently discovered and caused some performance problems at another customer.

Kind regards,

Christian Bartels.

[Former Member]

Thanks for the update.... I was on vacation for 1 month... that's why i could not reply. We are already having this PTF applied 5761SS1  SI45959. We are using XND driver less connectivity to connect the application servers. Are there any post upgrade activities to be carried out after upgrading to V6R1 and changing the H/W to Power 7 770 machine (upgraded from power 5plus 750).

Regards

Harish

[christian_bartels]

Whatever SAP is knowing about problems with the upgrade to IBM i 6.1 (V6R1) has been summarized in SAP Note 1148480. If the recommendations in that SAP Note do not help, it will be necessary to analyze the problem in more detail by a consultant or through a ticket in the SAP organization. It will be very hard to compare today's performance at V6R1 with the V5R4 performance of April 2012 directly, so I would focus on bottleneck identification in the current system rather than trying to compare with the status as it was 8 months ago.

Kind regards,

Christian.

[Former Member]

We have raised the issue to SAP as well as IBM . The solution provided by both the consultants are to provide additional H/W resources.

Regards

Harish

[Former Member]

Hi Harish,

I think, there needs to be an intensive performance analysis before we can useful recommend anything here. I do not see a good reason, why V5R4 should be a lot slower than 6.1 ... My impression would be:

Each OS needs a bit more ressources itself ... so, I would expect no change or a slight degradation in performance when upgrading the OS on the same hardware.

As we chatted a while ago, you know, that we cannot really help you just based on these kind of forum chats.

Regards

Volker Gueldenpfennig

[Former Member]

My impression also was system performance deteriorates slightly in new OS on the same Hardware. But it has deteriorated by 30 % which is not acceptable. I had put in this forum to understand I have missed any steps while carrying out the upgrade. We had parallely raised message with SAP.

Regards

Harish