SAP buffers has many swaps again

[Former Member]

Hello to all!

Six month ago some buffers in ST22 became red (many swaps). I tuned up the SAP buffers in ST02, it became white, but now it become red again.

Why ? What should I do ? How can I make best performance ?

[Former Member]

How long has this system been up? The startup date/time is on the line just above where you cropped the screenshot! If it has been up a long time, these numbers may not be anything to worry about.

What are the performance statistics like in ST03? If the average dialog response time is low, then you may not need to concern yourself at all with the buffer swaps.

Is this a production system or a dev/test system? What is running on the system? ERP? CRM? Something else? Help us to help you...

You will get buffer swaps on the program buffer. I don't get concerned unless the number is > 1000 per day.

Look at the history of the buffers with swaps to see if there was a single large event that triggered them, or if this is just normal workload. If it was a one-off event I wouldn't worry too much about it. Just keep an eye on the numbers to see if it happens again.

It is hard to give specific recommendations without knowing your system in more detail than we can go into here. That said, if this was my system here's what I would do:

• The export/import buffer looks a little small. Make it 100,000kB and see what happens. My production system buffer is 400,000kB and I still get swaps
• The CUA buffer is also a little small. Make it 40,000, or maybe more. Mine is 80,000 and I still get swaps
• My table buffers are 400,000kB combined and I have no swaps currently, after 5 months of uptime. You might want to increase your a little.

All those numbers are obviously determined largely by workload, and yours will be different from mine. Experiment. Increase them a little and see what happens. You might need to increase several times. If your server has the capacity, increase them a lot. If the RAM is there, use it.

Steve.

[Former Member]

Hi Steve!

System is running since 29.03.2014.

ST03 :

I think that 715 is the good time for dialog )

It is a ERP production server.

Program buffer history:

Ok, I will try to reboot the system and keep eye on it ) Thanks!

[Former Member]

Program buffer looks fine. After three months running I might be concerned about the import/export and field definition buffers, and not really about the others. Look at the history of those two and see if there was a big jump that might indicate a one-off event as the cause.

As for 715ms being a good dialog response time, I'm not so sure. SAP used to quote <1s as a target. I always aim for < 500ms. Right now my production system is running at 250ms. If you and your users are happy with the system's performance, then there's no problem. For me it looks like your system is overall a little too small, and not just lacking in RAM. Your CPU time at >300ms is higher than I'd like and indicates not enough CPU power. Or maybe users are just running compute intensive reports in the foreground and not the background?

Look at the buffer stats for your database also - ST04. You might be able to get your DB time down a little by increasing the DB buffers.

[Former Member]

Wow! 250 ms !

We use virtualization for our systems, and users often runs an intensive reports in dialog mode.

ST04:

[Former Member]

The DB buffer quality is OK, but I might be tempted to try and improve it a little. Add 50% to each and see what difference it makes.

Are there are resource limitations imposed on your servers by the VM system, particularly CPU restrictions? I'm still thinking CPU is the place to start if you want to improve things significantly. Memory config could be better, but isn't exactly bad at the moment. Any improvements from increasing buffer sizes will be small, I'd expect.

Steve.

[Former Member]

Ok Steve, I will try to increase the DB buffer. Yes, we have VM limitations - 8 cores on each VM when server has 64 cores.

[patelyogesh]

Hello,

You can get memory parameters you need to set by running following command

sappfpar check pf=X:\usr\sap\<SID>\SYS\profile\<SID>_DVEBMGS<XX>_SERVERCSC

run command at "X:\usr\sap\<SID>\DVEBMGS<XX>\exe"

This will give you list of memory parameters you need to set in your system

Some other Ref:

Virtual Memory Required by SAP System Components

Thank you

Yogesh

[Former Member]

Hi Igor,

Are you facing any performance issues?

Please go to ST02-Detailed Analysis Menu-For all servers.

Now observe the swapped objects field of the individual buffer say field definition,export/import for the last two latest days.

If the difference exceeds 10,000 swaps then this reason for concern.Please let us know if you find any significant delta in swapped objects .

Thanks

Sabya

[Former Member]

Hi SABYASACHI!

No, I have no performance problems.

Buffer history for the field description:

For the export/import:

[former_member188883]

Hi Igor,

SAP buffer tuning is an iterative process. You need to evaluate the swaps and check the history of usage. Based on that update required profile parameters.

From the screenshot I can see that lot of data upload activities have been performed which has impacted the buffer settings in SAP.

If the data load activities are not regular then you may not act immediately. Observe the system performance and user experience on performance and act on specific buffer settings only.

Hope this helps.

Regards,

Deepak Kori