SAP buffer (Transaction code ST02) performance - A lot of swapping

[Former Member]

Dear Consultant,

I am monitoring my system landscape and find that the the output of ST02 is

showing alot of swapping. I have gone thru some of SAP notes and conclude that

below parameters to be modified.

Please suggest does this solve my problem or some of the more parameters need to

be modified. The parameters & error screen shot is attached.

Buffer HitRatio % Alloc. KB Freesp. KB % Free Sp. Dir. Size FreeDirEnt % Free Dir Swaps DB Accs

Nametab (NTAB) 0

Table definition 91,68 6.796 19.990 6.648.863 24.366.289

Field definition 99,24 31.564 2.110 7,03 19.990 14.499 72,53 1.373.058 1.381.202

Short NTAB 99,99 3.625 1.709 56,97 4.997 472 9,45 1.072 5.739

Initial records 58,61 6.625 879 14,65 4.997 197 3,94 807.130 812.034

0

program 99,20 350.000 954 0,28 87.500 77.927 89,06 2.542.779 7.685.097

CUA 98,49 3.000 354 14,83 1.500 1.381 92,07 4.117.203 116.416

Screen 98,94 4.297 968 23,65 2.000 1.819 90,95 24.683 136.963

Calendar 99,98 488 366 76,57 200 48 24,00 0 302

OTR 80,43 4.096 3.279 99,94 2.000 1.991 99,55 0

0

Tables 0

Generic Key 98,94 29.297 1.623 5,85 5.000 794 15,88 34.078 23.610.875

Single record 92,89 10.000 311 3,17 500 439 87,80 15.192 15.738.209

0

Export/import 77,96 4.096 48 1,46 2.000 1.160 58,00 23.390.536

Exp./ Imp. SHM 97,06 4.096 3.085 94,03 2.000 1.999 99,95 0

======================================================================================================================

No of CPU 8

RAM 68 - GB

Operating System Sun Solaris 5.10

No of Users 286

Concurrent Users 125

SAP Version ECC60

Database Oracle 10.2.0.2

SAP Support Package level ABAP : 14 , BASIS : 14 & APPL : 11

SAP Kernel 700_REL

SAP Kernel Patch no 144

Buffer Settings

Parameters Current value Recommended value

abap/buffersize 350000 400000

rsdb/ntab/entrycount 19990 30000

rtbb/buffer_length 10000 20000

rsdb/cua/buffersize 3000 4000

zcsa/table_buffer_area 30000128 50000000

zcsa/db_max_buftab 5000 6000

zcsa/presentation_buffer_area 4400128 8000000

sap/bufdir_entries 2000 3000

rsdb/obj/buffersize 4096 8192

rsdb/obj/max_objects 2000 3000

rsdb/ntab/ftabsize 60001

rsdb/ntab/irbdsize 60001

rsdb/ntab/sntabsize 60001

Memory Management

Parameters Current value Recommended value

em/global_area_MB 255

ztta/roll_area 3000320 4000000

rdisp/PG_SHM 8192 8192

Regards

Vimal

[Former Member]

Hi

I am trying to change the parameter and getting error below warning in all parameters:

W rtbb/buffer_length factor 10 greater than default 10000

Also at the time of saving it recommends to change below to

parameters and come out without saving:

ipc/shm_psize_10 124000000

ipc/shm_psize_40 114000000

Error file attached for reference

Memory : 68GB

Regards

Vimal

[Former Member]

Hi Vimal

rsdb/ntab/ftabsize 60001

rsdb/ntab/irbdsize 60001

rsdb/ntab/sntabsize 60001

Change all these values to 80000

dont worry system will come up,suppose if doesnt u can always activate the older profile

dont worry,it will not be a big deal

just remember to have the backup of old profile

Hope this helps u, <Deleted by Moderator>

cheers

Rohit

DO NOT ASK FOR POINTS IN FORUMS

Please use complete words, and discontinue the use of SMS lingo like "u"

Edited by: Matt Kangas on Feb 23, 2009 8:37 AM

[Former Member]

Ho Rohit

Thanks for support

you have not mentioned anything about below parameters

rsdb/ntab/ftabsize 60001

rsdb/ntab/irbdsize 60001

rsdb/ntab/sntabsize 60001

my only concern is that after doing the above changes it should not happen that "system is not getting started " ...then will be a panic situation.

Please suggest.

Regards

Vimal

[Former Member]

Hai,

You can change the values since you have enough memory in the system.

But keep in mind to back up the existing Instance profile, if the system does not come up you can revert back to the old parameters and bring up the system.

Changing buffer parameters always needs intensive research and calculations before you modify them, so please be careful.

Regards,

Yoganand.V

[former_member185031]

After changing the parameter and before starting the SAP instace use sap tool SAPPFPAR to check the profile parameter is correct or not.

login to sidadm

sappfpar check pf=/sapmnt/SID/progile/<instance profile name>

Regards

Subhash

[Former Member]

Hello Vimal,

there seems to be no problem with memory,u can easliy increase the parameters as follows so that there is less swapping

I would suugest u to increase the parameters as follows:

abap/buffersize 350000 700000

rsdb/ntab/entrycount 19990 38000

rsdb/cua/buffersize 3000 5000

Let me know if it helps

Rohit

[Former Member]

Hi Rohit,

I have check the physical memory the details are as below

Physical memory Available : 67108864 KB

Physical memory free memory : 12692424 KB

Please suggest..

Regards

Vimal

[Former Member]

Couple of things more Vinay:

1. so to st06 and in the screen check for phsical memory free

this will guide how much memory in total that you should increase

suppose if you have 1 gb free memory and u decide to increase the buffer parameters.after calculating u decide that all the buffer parameters that u need to increase wil occupy 500 mb of free more space,then this might cause u the problem as u will have only 500 mb free which can cause u the performance issues

so u might reduce swapping of buffers to certain extent but it can increase OS swapping.

so just these things in comsideration while increasing your memory parameters

2. Also u can never bring all the buffers in non-red

u can just reduce the swapping and increase the perfromance by reviweing every 3 weeks or so

And please ignore my comment about program buffers in last post,export-import buffers are the ones which are affected by transports

Program buffers are the important ones and they should be taken into consideration,sorry for that

Let me know if u have any other questions

Rohit

[Former Member]

Hello Vimal,

there is no general rule for increasing these parameters.As u say there is lot of swapping you should increase these values to have a better perfromance.As a thumb rule we generally increase 20-25% of what they are now but it all depends on swapping.other thing that we have to take into consideartion os hit ratio,for most of the buffers it should be around 99% except program buffers.

Also u can expect lots of swapping in program buffers due to the transports in the system and should not be worried upon

These are the most imp. buffers in the system which perfromance:

Repository buffers (nametab buffers)

Table buffers

Program buffers

Roll and page file buffers

SAPgui buffers

my values would be

Buffer Settings

Parameters Current value Recommended value

abap/buffersize 350000 600000

rsdb/ntab/entrycount 19990 30000

rtbb/buffer_length 10000 20000

rsdb/cua/buffersize 3000 4000

zcsa/table_buffer_area 30000128 50000000

zcsa/db_max_buftab 5000 6500

zcsa/presentation_buffer_area 4400128 8000000

sap/bufdir_entries 2000 4000

rsdb/obj/buffersize 4096 8192

rsdb/obj/max_objects 2000 3000

Also make sure you keep monitoring system in every 3 weeks for buffering

Hope it helps

Rohit

[Former Member]

Hi Manoj

This is my production system.

This swapings was there since bigning .

We have not change any parameters since last 8 months .

Customer wants to make it non-red .

pl suggest

Regards

Vimal

[Former Member]

Hi,

Looks like this is not critical since you are surviving for last 8 months. But it is good idea to tune parameters and get the swapping to minimum. There are lots of factors you need to consider before starting tuning. Does it happens rarely? It there a pattern like only on the finacial month ends? Is there a enough RAM available with you? How much is the OS swap space allocated? Your platform details like Windows OS/Unix, 32 bit/64 bit etc. you need to prepare a plan and tune these parameters may be in stages. Please find few links which might help you in deciding the appropriate figures for your parameters.

http://help.sap.com/saphelp_nw70/helpdata/EN/02/9625e3538111d1891b0000e8322f96/content.htm

http://help.sap.com/saphelp_nw70/helpdata/EN/02/962831538111d1891b0000e8322f96/content.htm

http://help.sap.com/saphelp_nw70/helpdata/EN/34/d9c8b3c23c11d188b40000e83539c3/content.htm

http://help.sap.com/saphelp_nw70/helpdata/EN/34/d9c8b6c23c11d188b40000e83539c3/content.htm

Hope this helps.

Manoj Chintawar

[Former Member]

Hi,

Is it your production system? Was this working fine in last few days? Was there any change before this started like any upgrade or parameter tuning?

Thanks,

Manoj Chintawar