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author's profile photo Former Member
Former Member

Request additional RAM - Adivse me

Hello Team

Our team is planning to request additional RAM to resolve the performance issue in the sap instance.

Please help me to calculate how much memory can be requested.

OS : AIX 7.1

SAP : SAP NW 7.5

DB : Oracle 12.1

Total RAM allocated to the server : 20GB

Total Paging allocated to the server : 24GB

As per the ST02 - Detailed analysis - Storage

1)Storage Shared Between Work Processes = 3.792271614 GB

2)User storage for all work processes = 2.144439697 GB

3)Size of SAP executables (Disp+Work) = 0.085132599 GB

4)Size of Extended Memory = 6 GB

5)Maximum heap area for all work processes = 3.725290298 GB

Total (1+2+3+4+5) - SAP = 15.7GB

Please let me know Whether we need to include Heap memory in the total or we can ignore this and calculate only 1+2+3+4?

Oracle memory requirement (SGA + PGA) = 8GB

OS memory requirement = 3GB

Diagnostic agent memory Requirement = 1GB

Grand Total (SAP+ORACLE+OS+DAA) = 27.7GB

System is configured with

14 Dialog process (250MB Per work process)

4 BG process (750MB Per work process)

3 Update process (750MB Per work process)

1 spool process (750MB Per work process)

2 Update 2 process (750MB Per work process)

If we calculate the work process, it will come to around 11GB.

I am little bit confused whether we need to add this 11GB in the Grand total(27.7GB) =38.7GB

Please let me know whether i have to request additional 8GB of RAM or 18 GB of RAM to avoid performance issue?



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3 Answers

  • author's profile photo Former Member
    Former Member
    Posted on Sep 07, 2016 at 06:25 PM

    Hi Samb,

    To get the hardware requirements you can make use of the SAP sizing tool

    Also refer to the below links for more information.

    Right-Sizing Your HardwareQuick Sizer - Getting started | SCN
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  • Posted on Sep 15, 2016 at 07:53 AM

    As Former Member mentioned that you need to 1st comply with the hardware sizing as described, I would recommend that too.

    According to your current hardware sizing, the current RAM size just looks fine to me. Here you just need to focus on some fine tuning of your system. So, that your db & system memory remains available every-time for use, you also need regularly checking on like, critical db objects, data-collates, SAP jobs unfinished & re-running at production hours which can also degrade system performance matter, etc. For example, for an AIX system, I can recommend here,

    $ lsattr -El sys0 | grep realmem


    # svmon -G

    Inside the SAP system, I can also recommend to run the report RSUSR405 in SE38 to reset buffer from time to time, if only felt required.



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  • Posted on Sep 19, 2016 at 11:02 AM

    Former Member, Hope that you got your answer by now or else please post an update. If yes, then I would like you to please close this discussion thread by marking answers as Correct or Helpful. Note: That for a new issue you can always go ahead & try creating a new discussion thread.



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