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MaxCPUs and DBANALYZER

Hi Everyone,

We are running a new productive system with 4 Intel E5-4640 CPUs

providing 64 CPUs (32 CPUs with Hyperthreading activated).

I've made a DBANALYZER-Check which keeps complaining

parameter MaxCPUs:

'MaxCPUs' (24) exceeds number of physical CPUs (4)!

I'm now a little bit confused because I do not think that it's the best

way to configure "physical" instead of "logical CPUs".

Now: What's the right configuration if this server is a central instance?

By the way: I'm using the latest dbanalyzer_InstanceParameterCheck.cfg

download from SAP Note.

Thanks in advance.

Kind Regards,

Carsten Loeffler

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1 Answer

  • Oct 22, 2014 at 11:33 AM

    Hello Carsten,

    please let me know which database version you are using and if the Analyzer message is labeled as 'info' or 'warning' or has no preceeding indicator at all.


    We will probably change the message text somewhat. It originates from the early times of hyperthreading and multi core CPUs when using more logical CPUs than physical CPU cores could lead to a performance bottleneck - (edit 1)of course times have changed since...


    Edit 2:
    ok, I have to clarify this a bit. We still write a 'I' type info when the number of physical cores is below your usable MaxCPUs value. This is, because hyperthreading might have some negativ impact on some OS platforms and CPU types.
    But this is only marked as 'I', so not warning.

    Regarding your case there are two things we will change:

    1. The exclamation mark '!' at the end of the line is not necessary, because it might imply that some user action is needed. So we make this message line less 'complaining' :-)

    2. This message should not have appeared at all, because is is supposed to apply to the total of physical cores only, which in your case is 32 (4 physical CPUs with 8 physical cores each). So it seems that the info message is wrongly based on the 4 physical CPUs).

    I will get back to you once I have news - we will investigate this...

    Thorsten

    Message was edited by: Thorsten Zielke

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