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Thread: size buffers

  1. #1
    Join Date
    Dec 2002
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    Thumbs up Unanswered: size buffers

    hi,

    please I need to calculate the size of buffers, who have help me.

    thank you.

    Georgi

  2. #2
    Join Date
    Aug 2002
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    Belgium
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    What buffers do you want to calculate?

    onstat -g seg
    will display an overview of the main memory segments.

    onstat -g mem
    displays the memory size per pool.
    rws

  3. #3
    Join Date
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    Originally posted by Roelwe
    What buffers do you want to calculate?

    onstat -g seg
    will display an overview of the main memory segments.

    onstat -g mem
    displays the memory size per pool.
    I need to calculate el value of buffers of file onconfig.std

    Thank you.

  4. #4
    Join Date
    Jun 2002
    Location
    Ireland
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    12
    Hi,

    A formula for calculating BUFFERS is:

    Buffers = (RAW_BUFFERS/LRU_MIN_DIRTY)*100,

    where:

    RAW_BUFFERS = ((NUMBER_OF_DAYS * (NUMBER_OF_ROWS (for a day) * PAGES_FOR_TABLES))

    Informix recommend NUMBER_OF_DAYS be set to 2.

    Hope this helps.

  5. #5
    Join Date
    Aug 2002
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    Belgium
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    I always use trial and error. The most important thing is to keep the checkpoint duration as small as possible.
    If you have a big chunk of memory available in your system, bring up the BUFFERS parameter and fine-tune with LRU/CLEANERS/LRU_MIN_DIRTY/LRU_MAX_DIRTY.
    Make sure that your checkpoint duration stays low.
    Be aware that not only the BUFFERS parameter affects the total amount of memory allocated by the informix server.
    rws

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