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  1. #1
    Join Date
    Jul 2005
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    103

    Unanswered: Restrict CPU Usage

    AIX 5.3
    DB2 8.2

    Is it possible to restrict DB2 to a single processor when the box it is on can have more than one processor in use?

    Thanks.

  2. #2
    Join Date
    Jun 2003
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    Toronto, Canada
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    Provided Answers: 1
    Micropartitioning?
    ---
    "It does not work" is not a valid problem statement.

  3. #3
    Join Date
    Jul 2005
    Posts
    103
    I am not sure what you mean by micropartitioning. MS SQL Server has the ability to be configured to use 1, 2, 3, or 4 processors on a box with 4 processors. I am simply looking for a DB2 (on AIX) equivalent configuration option.

  4. #4
    Join Date
    Jan 2003
    Posts
    1,605
    Hi,
    try using DB2PROCESSORS db2 variable as suggested in: http://www.thescripts.com/forum/thread182550.html
    Hope this helps,
    Grofaty

  5. #5
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    Provided Answers: 1
    DB2PROCESSORS is only valid on Windows, I believe. Also, as mentioned under that link, it's a performance optimization trick and it is not necessarily good enough for IBM from the licensing standpoint.

    Micropartitioning is an AIX feature that allows you to create a logical partition in the operating system, essentially a virtual machine, and assign a certain number of processors to it. If you install DB2 on that logical partition the license applies to the number of logical processors allocated to that partition, regardles of how many physical processors are installed.
    ---
    "It does not work" is not a valid problem statement.

  6. #6
    Join Date
    Jul 2005
    Posts
    103
    Thanks. According to your definition of micropartitioning, we are doing it. What I have not shared is that we have a p570 that is broken in to various LPARs. As I am sure you are aware, the processors on a p570 can be dedicated or shared among the LPARs. Our DB2 license is for 1 CPU so we have this LPAR capped such that it can not borrow additional CPU from the shared pool. However, we would like to cap DB2 (if possible) only so that the applcation that is also on this box can borrow CPU from the shared pool if needed.

  7. #7
    Join Date
    Jul 2005
    Posts
    103
    Actually, re-reading your micropartitioning definition, we are not doing it (if I get it). To do as you suggest, we would create a logical partition on the LPAR is question, correct?

  8. #8
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    Provided Answers: 1
    LPAR is a Logical PARtition.

    If I understand you correctly, you run DB2 and some other application in the same LPAR, and would like to limit CPU for DB2 but not for that application? Sorry, that's not going to work. There's no "soft" limit in DB2, you can only manipulate CPU resources at the LPAR level, not at the application level. In general, I don't think it is a good idea to run DB2 and its client application in the same partition.
    ---
    "It does not work" is not a valid problem statement.

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