SAP performance issues

[JAMpe]

Hello,

I have users dissatisfied with a SAP System (ERP 6.0 EHP4 / NW 7.01) so I'm being asked to check it. I know that there's many transactions to check like ST03N, ST06N, ST02, etc but I'd like to know which should be the best approach, I mean what should i look first? I hope you can share your experience.

Regards,

JAM

Platform:

OS: AIX 6.1

DB: DB6 9.7

btw: I don't have a solution manager monitoring the system.

[Reagan · Accepted solution]

Hello

If the problem is with one specific Tx then you need concentrate only on the Tx.

If the problem is with the overall system performance then you need to analyse the SAP, DB2 and AIX.

First check whether the hardware is properly sized. Check the memory assigned to the DB, SAP and the available memory on the system.

Are there any other applications or SAP systems running on this server ? If yes you need to make sure that the memory is sufficient for all the systems running on the server.

Check whether the system parameters are set according to the recommendations.

Make use of the topas command to understand the overall system performance like CPU, Memory, Disk, Paging, etc.

Also take the NMON statistics and review that.

Use Tx ST03N and check the Response times. If the response times are bad then check where exactly the work process is taking time.

Check the database cache hit ratio. If the hit ratio is below 95% then consider tuning the database.

I cannot provide more information on the DB2 side as my knowledge on DB2 is very limited. So the best would be to get hold of a DB2 specialist and ask him / her to do a performance analysis.

Check the ABAP buffers in Tx ST02. If the hit ratio is below 95% then consider increasing them.

Do you have additional AS's ? check whether the response times for the AS's.

If there is a problem with the wait time then the problem could be lack of work processes.

These are just some hints.

Good Luck

RB

[JAMpe · Accepted solution]

Thank you all for the information, I wlil start with transactions ST06N and ST03N for initial hints.

Does anyone have a guide/blog/info about how to analize transaction ST03N and understand it?

Are there thresholds defined for minimum response times? (according to SAP).

Regards,

JAM

[Reagan · Accepted solution]

ADM315 - Workload analysis contains a lot of information about this.

To start with I would say have a look at these:

http://blog.sapadmin.co.in/?p=248

http://www.saptechies.org/performing-workload-analysis/

Regards

RB

[JAMpe · Accepted solution]

Thanks for the info Reagan.

Now I'm checking the memory parameters and I'd like to know which should be acceptable values assuming the non standard transactions are well developed and the standard transactions are well used (for example, using filters)?

According to my configuration I have the following:

Number of workprocess: 45 (DIA + non DIA)

Quotas for EM in a WP:

ztta/roll_extension_dia ~ 4.5  GB

ztta/roll_extension_nondia ~ 4.5  GB

Quotas for Heap memory in a WP:

abap/heap_area_dia ~ 4.5 GB

abap/heap_area_nondia ~ 4.5 GB

Others:

em/initial_size_MB ~ 40 GB

rdisp/ROLL_SHM ~ 256 MB

rdisp/ROLL_MAXFS  ~ 256 MB

rdisp/PG_SHM ~ 256 MB

rdisp/PG_MAXFS ~ 256 MB

abap/heaplimit ~ 40 MB

I think the quotas for EM and Heap are to High, what do you think? Does SAP suggest anywhere standard values than the defaults?

I've seen DIA users going in PRIV mode with standard transactions, so I guess they may be using the transaction in a wrong way, right? I mean, not using filters and etc.

I know that after going PRIV mode the heaplimit can release the memory allocated by a WP restart, but should this value be too low? Is there a disadvantage if the WP restarts regulary?

Another question regarding DB space: I have almost all my filesystem at 90% (SAPDATAs), does this give poor system performance? Is this documented anywhere?

Regards,

JAM

[Reagan · Accepted solution]

Hello JAM

As long as you the system is configured with enough memory and CPU you can. The standard values are mentioned in the below notes.

425207 - SAP memory management, current parameter ranges

146289 - Parameter Recommendations for 64-Bit SAP Kernel

1972803 - SAP on AIX: Recommendations

I would set the ztta/roll_extension_dia and ztta/roll_extension_nondia to 3GB or 4GB (maximum) and set the heap to 2GB.

The filesystem sapdata is used by the database and this doesn't create any performance problem if the used space is above 90%. As long as you have the space in the volume group you can extend the filesystem with additional space for the DB to grow.

If the work processes are constantly getting into PRIV mode with the above memory configuration then I suspect a memory leak.

Try updating the kernel if the system is running on old version of kernel.

Also check the ulimits of the sidadm user.

Regards

RB

[JAMpe · Accepted solution]

Thanks for the input Reagan, As my OS is AIX I'm also configuring the Extended Memory:

So I'm changing the following parameters:

ES/TABLE = SHM_SEGS

ES/SHM_SEGS_VERSION = 2

I want to configure 32GB for extended memory so the parameter "em/initial_size_MB" is still the proper one?

With this configuration, is parameter em/max_size_MB deprecated now and I have to use EM/TOTAL_SIZE_MB instead?

Regards,

JAM

[Former Member · Accepted solution]

You need to use EM/TOTAL_SIZE_MB to configure extended memory size.

[Reagan · Accepted solution]

Hello JAM

ES/TABLE = SHM_SEGS

ES/SHM_SEGS_VERSION = 2

Setting the above parameters will make the memory consumption of all the work processes (dialog and non-dialog) in the same way.

The parameter EM/TOTAL_SIZE_MB should be set in the profile to limit the EM usage on AIX

517006 - Standard value of EM/TOTAL_SIZE_MB is 256 GB

445533 - Lots of extended memory on AIX (64 bit)

Regards

RB

[JAMpe · Accepted solution]

Hello everyone,

My question was this one:

Before activating "ES/TABLE = SHM_SEGS" and "ES/SHM_SEGS_VERSION = 2"

I used to configure EM with this parameters:

em/initial_size_MB

em/max_size_MB

Now, after activating "ES/TABLE = SHM_SEGS" and "ES/SHM_SEGS_VERSION = 2",

what will be the parameters to configure EM?

em/initial_size_MB?

EM/TOTAL_SIZE_MB?

What about em/max_size_MB? Is it deprecated now?

Regards and Thank you for all your patience.

JAM

[Reagan · Accepted solution]

Hello

You need to set the parameter EM/TOTAL_SIZE_MB to control the EM usage for AIX based systems.

Configuration for AIX - SAP Memory Management (BC-CST-MM) - SAP Library

What about em/max_size_MB? Is it deprecated now?

You need to use EM/TOTAL_SIZE_MB. Check this SAP note

789477 - Large extended memory on AIX (64-bit) as of Kernel 6.20

146289 - Parameter Recommendations for 64-Bit SAP Kernel

Regarding the em/initial_size_MB parameter read these SAP notes.

425207 - SAP memory management, current parameter ranges

712664 - Extended memory memory areas larger than 2GB

835474 - More than 32 GB extended memory

1014010 - EG memory up to 32 GB (em/global_area_MB up to 32000)

785365 - Extended Global Memory (EG) increased from 2 GB to 8 GB

Back to the performance issue check whether the AIX is configured as recommended.

Make use of these SAP notes.

1972803 - SAP on AIX: Recommendations

1780029 - High physical memory utilization on AIX

Also check whether the DB2 is configured properly.

Regards

RB

[Former Member]

Check ST06, ST03N and ST04 for clues.

Share the system configuration (HW, OS) and then the user load details.

It might be because of undersized resources!

Regards,

Nick Loy

[Former Member]

Hi J A,

Please check below links ,i hope it will help you :

In case ,you still have any further concerns please do revert back.Thanks in advance !

Best Regards,

Praveen Sriavastava