IBM i Global

IBM i 

A space for professionals working with IBM’s integrated OS for Power systems to exchange ideas, ask questions, and share expertise on topics like RPG and COBOL development, application modernization, open source integration, system administration, and business continuity.


#Power


#IBMi
 View Only

  • 1.  how to calculate memory size for an IBMi partition ?

    Posted Fri September 01, 2023 11:46 AM

    Hi All,

    I know the size 32 GB Memory for Power 8 CPU, 64Go for Power9 etc ...

    Why ?

    What is it the rule ?

    Perhaps by CPW ? HTTP Process ? Java Process ?

    Regards,

    Henri Bouvier



    ------------------------------
    Henri Bouvier
    ------------------------------


  • 2.  RE: how to calculate memory size for an IBMi partition ?

    Posted Fri September 01, 2023 08:29 PM

    Henri

    I would say it's just a rule-of-thumb and nothing more. As of POWER8 core, I personally use 8-16GB per core for low and medium workload. 32GB for heavyweight workload. 



    ------------------------------
    Chance favors only the prepared mind.
    -- Louis Pasteur
    ------------------------------
    Satid S.
    ------------------------------

    Original Message


  • 3.  RE: how to calculate memory size for an IBMi partition ?

    Posted Mon September 04, 2023 02:56 AM

    Hi Satid,

    Thank you for your feedback.
    We estimate the memory size of 5Mo per CPW.
    So I would say it's good practice, but it's not a rule.

    Regards,

    Henri B.



    ------------------------------
    Henri Bouvier
    ------------------------------

    Original Message


  • 4.  RE: how to calculate memory size for an IBMi partition ?

    Posted Mon September 04, 2023 04:55 AM
      |   view attached

    Hello Henri,

    No matter what you decide to give, depending on the workload it might be sufficient, too much or too little. 

    When running a representative workload, when having Collection Services configured. Looking at the graph "Memory Usage by Pool" will answer this question.

    All you have to do is fire up Navigator for I => Performance => Investigate Data = > Enter the string "Memory" under Perspective.

    I have included a screenshot of this graph to get you going.

    I can only hope this reply was helpful.



    ------------------------------
    Rudi Van Helvoirt
    ------------------------------

    Original Message


Related Content