memory management in SAP/Oralce/Solaris

[Former Member]

Hi experts!

Can you advise to me how can I regulate whole memory (SAP Application and Oracle)

what parameters may allow to customize memory for SAP and Oracle.

Is it only few parameters in st02?

Regards,

Artem

[Former Member · Accepted solution]

Artem,

Another method is, schedule a GoLive session or Optimization session with SAP Support and they will send you a detailed report on the recommendations for your system.

Cheers,

Nisch

[Former Member]

😕

[markus_doehr2]

What do you mean with that?

Markus

[Former Member]

I mean that I found some parameters wich, as for me, seems very important. But I didn't find these parameters in answers

For example, em/initial_size_MB. This parameter was set too low during installation "on automatic mode"...

[Former Member]

Thats the basic SAP memory parameter governing how much RAM the system can take up.

www.google.com

http://help.sap.com/saphelp_nw2004s/helpdata/en/02/9626e7538111d1891b0000e8322f96/content.htm

em/initial_size_MB: Extended Memory Pool Size Locate the document in its SAP Library structure

Use

This value specifies the extended memory pool size that the SAP system manages for the SAP Extended Memory.

The value is stated in megabytes.

Integration

Ideally, this pool is large enough to contain the sum of all the user contexts. The pool must always be larger than the size of the parameter ztta/roll_extension. This parameter specifies how much extended memory can be allocated from the pool to one user context.

If the pool is used up, heap memory is allocated (see Private Memory and Allocating Memory for User Contexts). The work process switches to the PRIV mode and is reserved exclusively for the current user context. After processing the user context, the work process might restart automatically if the process size specified in abap/heaplimit is exceeded.

Activities

The default value is platform-specific and is determined dynamically. The default value is specified in transaction RZ11. This value should not normally be changed.

The value must be between 32 and 8096.

Kep in mind the following notes about the pool size:

Recommendation

Ensure that the pool is 10 to 15 times as big as ztta/roll_extension. The exact value depends on the available swap space and the number of users in the host system.

Note

The swap space must be sized so that it can contain the SAP extended memory and has enough space for the SAP usage of heap memory (see Swap Space Requirements). There must also be enough space available for competing system users outside of the SAP system. The swap space must also be large enough to ensure a safety reserve.

Edited by: James Ibbotson on Jul 22, 2008 3:49 PM

[markus_doehr2]

I gave some note numbers with parameter recommendations - which also include that parameter:

146289 - Parameter Recommendations for 64-Bit SAP Kernel

<...>
      3. Implement the SAP profile parameters as follows:

    em/initial_size_MB      1024 up to 1TB (note 835474)
    em/blocksize_KB        2048, 4096 or 8192 (note 835474)
    ztta/roll_first        1
    ztta/roll_area          6500000 
<...>

So actually that information was there - indirectly

Markus

[markus_doehr2]

> Can you advise to me how can I regulate whole memory (SAP Application and Oracle)

> what parameters may allow to customize memory for SAP and Oracle.

> Is it only few parameters in st02?

Few parameters? Execute the report "RSPARAM" and you will see "a few" parameters to tune

SAP has its parameters to run and Oracle has them too.

Check the following notes:

Oracle:

Note 830576 - Parameter recommendations for Oracle 10g (<= 10.2.0.2)

SAP:

Note 146289 - Parameter Recommendations for 64-Bit SAP Kernel

Operating system:

395438 - Parameter settings for Solaris 9 and below

724713 - parameter settings for Solaris 10

Markus

[Former Member]

Dear Markus,

do you know how can I define certain quantity of RAM for SAP application?

Can I define whole parameter for SAP and Oracle?

Thanks

[markus_doehr2]

Please check the note about the parameters for a 64bit SAP system I gave you. There you will find the parameters, that need/can be set to configure the SAP system for a certain amount of memory.

Oracle on Solaris uses DISM (memory class), that memory is "fixed" and is not swapped out as opposed to the memory SAP uses. How much each of them needs for best performance is something either an EarlyWatch can find out (due to the experience and formulars they have) or by tuning the system iteratively.

The memory needed for a fast systems heavily depends on how you use the system, how many different "modules" and "components" are implemented and your general workload. This can´t be evaluated and configured theoretically but only after the system ran for some time.

Markus