SAP Slows probably due to memory

[Former Member]

hi basis experts,

Our PRD server is slowing a bit, i think it was because of memory problems. At OS level, we have 16GB physical memory. During peak times, the memory has only 7BG available left. we have almost 200 users with upto 300 modes. In RZ10, I have assigned parameter PHYS_MEMSIZE to 8192 because it was half the 16GB memory that we have.

Does the 16 GB memory enough for our number of users? I also want to know if I've set the correct value to that parameter. Also, please tell me other parameters which I have to activate so that I could accomodate 200+ users with 300+ modes.

Thank you in advance!

[sunny_pahuja2 · Accepted solution]

Hi,

Check in ST02 and accordingly fine tune memory parameters.

Thanks

Sunny

[Former Member · Accepted solution]

Hi,

In addition to what Sunny suggested, I would like to add that, please go through SAP Notes.

For example, note 941735 is for Liunx OS.

Likewise, find the appropriate note for your OS and go per SAP recommendation.

Regards,

Sujit.

[Former Member]

Thanks for all of your help, analyzing st02 buffers really heped me alot. It seems I really have to increase physical memory.

[Former Member]

If you have a working Solution Manger system you can run the SAP Technical Performance Optimization report in the Self Delivered Services. I've found it gives surprisingly good recommendations.

Otherwise keep an eye on the hit ratios in ST06 and DB02. And you can always use more RAM.

For reference I've got about 300 users and 40GB of RAM (DB & CI on one host, 30/70 memory split) and I still get some swapping.

[Former Member]

hi experts,

i have adjusted the config successfully and lessen the swaps on st02 but still the system slows a bit. Can you help me in sizing the hardware? I think I really have to upgrade our memory.

Details:

Memory = 16GB

Users = 250

Modules = SD,FICO,MM

Please let me know of other data to be considered on sizing.

Thank you.

[Former Member]

The SWAPS will gradually go up with time .

Have a more Detailed Analysis .

Check out Metrics Such as

*Extended Memory Usage

*Heap Memory Usage

*Roll in / Roll out Swaps

*The Memory Parameters

*No. of Users Using PRIV Memory

*Database Bottlenecks

*Network Load

Also , could you mention which OS are you Using ???

If Possible , Could you paste a Screen Shot of the ST02 Transaction .

Is it a 2-Teir or 3-Teir landscape ??

Regards,

Ashish .A. Poojary

Edited by: Ashish Poojary on Mar 22, 2011 12:49 PM

[Former Member]

Hi Karshbax,

First of all, you need to find the cause of the performance problems. Have a look at st06 and st02 to check CPU use history, memory usage, and *very important*, the use of buffers. 16GB sound quite enough to me for 200 users working on FI, CO, MM and SD.

Check ST02 for buffer usage, remaining free size, remaining entries, etc. Probably you'll need to increase the buffer size parameters. If you are working in a UNIX system you'll need to increase the ipc sizes too.

Regards

Francisco

[Former Member]

hi arish,

I've already checked those metrics except for the DB bottleneck, where could I check that? Also what is a 2-teir 3- teir landscape? not familiar with the term.

I'm using windows 2003 server.

from st02

Roll area: CUrr.Use%= 6.90% / HitRatio% = 97.18%

Page area: Curr.Use%= 11.29% / HitRatio%= 84%

Extended Memory: Curr.Use%= 21.01% / In Mem[kb] = 8,384,512

Heap Memory: zero values

I appreciate your help

[Former Member]

hi francisco,

regarding buffers, is it necessary to use commands /$tab and /$sync? if yes, how often should I use these?.

THank you for your help

[Former Member]

Hi again,

If you execute /$tab and /$sync you'll flush the buffers contents, and that won't help.

What you have to do is check the buffer use in ST02, percent of used space and percent of used entries. If one of the buffers has much swap (red figures) you'll probably have to increase the parameters associated to it. Usually the most important for performance are table (generic key and single records) and program buffers. If you don't know which parameters you have to change, double click on a buffer in st02 -> and then click on "current parameters".

Regards

Francisco

[markus_doehr2]

The first thing I'd check is ST02 - Detailed Analysis - Memory

If you see lots of swapping (in and out) you have too less memory - despite the configuration.

Markus

[Former Member]

thanks sunny for, you gave me an idea on what to do.

But still my question isnt answered. How much memory should I allocate on parameter PHYS_MEMSIZE for us to have optimum performance on SAP?

kindly suggest, thank you in advance!

[sunny_pahuja2]

Hi,

As such there is no standard value that you can set. You need to observe load on the system and accordingly increase its value. This is a continuous monitoring that you can improve on time. There is no standard formula.

Thanks

Sunny