GPFS performance - Aix

This is a discussion on GPFS performance - Aix ; Can anyone explain the following results? Test1 I wrote a simple program that opens a file with around two and a half million lines in it and writes the contents to 3 different files depending on the contents of the ...

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Thread: GPFS performance

  1. GPFS performance

    Can anyone explain the following results?

    Test1
    I wrote a simple program that opens a file with around two and a half
    million lines in it and writes the contents to 3 different files
    depending on the contents of the line. This program opened 4
    different
    file pointers at the start of the program and kept them open
    throughout.
    The average time for Test1 to run was as follows:

    Normal AIX JFS - 15 Sec
    GPFS - 20 Sec


    Test2
    I rewrote the program in Test1 with the only difference being that
    every
    time I wanted to write to a file I opened and then closed a new file
    pointer. The average time for Test2 to run was as follows:

    Normal AIX JFS - 91 Sec
    GPFS - 24 Mins 31 Sec

    Clearly the opening and closing of files seems to give something on
    GPFS .

    Any ideas what might be causing this? __.____._

  2. Re: GPFS performance

    On Jun 3, 10:25 am, Loial wrote:
    > Can anyone explain the following results?
    >
    > Test1
    > I wrote a simple program that opens a file with around two and a half
    > million lines in it and writes the contents to 3 different files
    > depending on the contents of the line. This program opened 4
    > different
    > file pointers at the start of the program and kept them open
    > throughout.
    > The average time for Test1 to run was as follows:
    >
    > Normal AIX JFS - 15 Sec
    > GPFS - 20 Sec
    >
    > Test2
    > I rewrote the program in Test1 with the only difference being that
    > every
    > time I wanted to write to a file I opened and then closed a new file
    > pointer. The average time for Test2 to run was as follows:
    >
    > Normal AIX JFS - 91 Sec
    > GPFS - 24 Mins 31 Sec
    >
    > Clearly the opening and closing of files seems to give something on
    > GPFS .
    >
    > Any ideas what might be causing this? __.____._


    Cluster configuration ( Single node, double, nsd .... )
    Which GPFS Version
    What Blocksize
    What PagePool size
    Which mount options

    Cheers
    Hajo

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