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  1. #1
    Join Date
    Jun 2010
    Posts
    2

    Unanswered: Clarification - dsync on Windows

    I'm investigating performance issues on an ASE 15 server running on Window 2003. Setting dsync false on the devices is making a significant performance difference. e.g. an insert that takes around 5 mins with dsync false takes 30 mins with dsync true.

    Is this expected? The sybase docs indicate the dsync setting is ignored on Windows:
    SyBooks Online

  2. #2
    Join Date
    Jun 2010
    Posts
    2
    Just following up on this...

    The SAN monitoring tools show clearly the dsync device settings makes a difference in Windows. With dsync on, the write IO comes through in 2KB blocks as expected. With dsync off, the write IO is coming through delayed and in much larger block sizes.

    So here's, a tip: for test/dev databases I'd highly recommend experimenting with dsync = off for the devices. You need to restart Sybase for the change to take effect. Makes a big difference to performance.

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