Extended memory query

[former_member759680]

Hello,

We have ECC 6.0 on AIX 5.3 and Oracle

Parameter em/initial_size_MB = 512

ztta/roll_extension = 2000000000

Documentation states that -

Dependencies:

ztta/roll_extension only takes effect if its value is lower than

%%em/initial_size_MB%%.

So, as per my undersatnding, total EM = 500 MB.

But I am not sure how much EM would be allocated to each User context?

Also, in ST02, I see that

Extended memory - MaxUse(KB) = 2424832

I am not sure from where is it taking EM = 2.4GB

Regards,

Gautam.

[Former Member]

HI,

each user context data move to not only these EM/MAX_SIZE_MB, when a user loging, it went to zttz/first than zttz/roll exentension than zttz/roll_area and abap /heap_ dia now think how the process is going on ...

EM/MAX_SIZE_MB is realated to ur os version and the sap patch level.

those paarmeter are all depend to ur hardware setup..

reagrds

brindavan

[Former Member]

with AIX and ES/TABLE=SHM_SEGS the parameter for extended Memory is EM/TOTAL_SIZE_MB

look at note 789477

[former_member759680]

Hello All,

Thanks a lot. EM in AIX is a lot clear now for me.

But I noticed in ST02, for HEAP, the value of In Memory and Max Use both are 0

However the heap parameters are all correct:

abap/heap_area_dia 2000000000 Byte

abap/heap_area_nondia 2000000000 Byte

abap/heap_area_total 4000000000 Byte

abap/heaplimit 40000000 Byte

Is there some other parameter that controls the Heap memory usage?

[Former Member]

Nothing to worry about, AIX is using EM before it needs heap memory, even for batch processes.

So it's likely there wasn't any heep memory needed since your last system start.

[former_member759680]

Addition to my previous post with Heap parameters:

In spite of all heap parameters set, it is dumping with Assigned Heap = 0

Runtime Errors         SYSTEM_NO_ROLL 
Date and Time          19.09.2011 19:25:55 

 Short text 
     Unable to fulfil request for 2281701376 bytes of memory space.

How to correct the error 
    Try to decide by analysis whether this request is 
    reasonable or whether there is a program error. You should pay 
    particular attention to the internal table entries listed below. 

    The amount of storage space (in bytes) filled at termination time was: 

    Roll area...................... 16128 
    Extended memory (EM)........... 2109647232 
    Assigned memory (HEAP)......... 0     
    Short area..................... " " 
    Paging area.................... 24576 
    Maximum address space.......... 4294967295

[Former Member]

Hi Gautam,

em/initial_size_MB: should be significantly larger than ztta/roll_extension.

http://help.sap.com/saphelp_nw04/helpdata/en/02/9626b3538111d1891b0000e8322f96/content.htm

How much RAM has been allocated for this LPAR?

How many other instances running on this machine?

Br,

Venky.

[former_member759680]

Hello Venkatesh,

em/initial_size_MB: should be significantly larger than ztta/roll_extension.

I agree to that

But could you please answer my questions in the current scenario, with the current parameter settings?

How much RAM has been allocated for this LPAR?

20GB

How many other instances running on this machine?

1

[Former Member]

Hi Gautam,

What is the value of em/max_size_MB?

Refer to the Note 425207 - SAP memory management, current parameter ranges.

Could you please paste the output of the following

1. ST02 -> Double Click on Extended Memory -> Overview

2. ST02 -> Double Click on Extended Memory -> Quotas

3. ST02 -> Double Click on Extended Memory -> Current parameters.

Br,

Venky.

[sunny_pahuja2]

Hi,

If i would have been at your place then simply i will analyze ST02 and will see how much swaping is there and based upon system resources and system load will increase its value. And after that will monitor the system if there will be any chance to improve it further.

There is no hard and fast formula to find the value if these parameters based on your system resources. Its an iterative process which needs continuous improvement.

Thanks

Sunny