sap memory

[Former Member]

hello

I have a sap system where i want to shrink allocated memory . On sappfpar check pf= ....i have the following answer

Shared memory resource requirements estimated

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

Total Nr of shared segments required.....: 30

System-imposed number of shared memories.: 1000

Shared memory segment size required min..: 319488000 ( 304.7 MB)

System-imposed maximum segment size......: 3741319168 (3568.0 MB)

Swap space requirements estimated

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

Shared memory....................: 1248.2 MB

..in pool 10 122.2 MB, 95% used

..in pool 40 103.6 MB, 95% used

..not in pool: 1013.6 MB

Processes........................: 179.4 MB

Extended Memory .................: 5096.0 MB

-

---

Total, minimum requirement.......: 6523.6 MB

Process local heaps, worst case..: 1908.0 MB

Total, worst case requirement....: 8931.6 MB

Errors detected..................: 0

Warnings detected................: 1

How to change values for "System-imposed maximum segment size", "Shared memory segment size required min","System-imposed number of shared memories" , "Total Nr of shared segments required"?

Regards

[thunder_feng]

Hello

SAP system memory tuning does not depend on the OS platform much.

so this should be a general issue.

It is NOT recommended to shrink the size of SHM, as if it is not enough, your system will not work, not only you just get a

worse performance.

Additionally some of the SHM is hard-coded in the kernel as far as I know.

Therefore if you want to shrink the memory used by the system, try to consider change the memory used by the work processes.

or the number of configured work processes.

Thanks

Thunder

[former_member59864]

Memory confguration depends of many factors, such as you physical memory, system type 32 bits, 64 bits, operating system etc, for now as i can see in the output of sappfpar you are using 95% of the memory allocation in pools therefore is not an option to shrink memory in this area.

Regards

[Former Member]

Hi,

What is your OS?

You may want to refer SAP Memory Management

https://help.sap.com/saphelp_nw04s/helpdata/en/02/96253c538111d1891b0000e8322f96/frameset.htm

Regards,

[Former Member]

my os is linux (sles 10 sp2)

[Former Member]

I recommned to follow

Note 103747 - Performance: Parameter recommendations as of Release 4.0

Note 386605 - SAP Memory Management for Linux

Other than SAP consider OS parameter as well.

All related parameter names are mentioned there.

Regards,