Re: Disk I/O Performance

From: Kristofer Pettijohn (krishopper_at_cybernetik.net)
Date: 10/19/04

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    Date: Tue, 19 Oct 2004 16:02:41 -0500
To: Jo?o Carlos Mendes Lu?s <jonny@jonny.eng.br>

    On Tue, Oct 19, 2004 at 04:45:03PM -0300, Jo?o Carlos Mendes Lu?s wrote:
    > I'd say that you have to check which CCD chunk size is best for
    > your needs. The manual for vinum recommends avoiding chunk sized to a
    > power of two, which is probably the first big mistake of everybody.

    I've tried a wide range of chunk sizes, from 128kB to 64MB.. also have
    been avoiding powers of 2.

    > Try mounting with option noatime, if you haven't already. And use
    > the largest block size possible when formatting. Last time I read about
    > there was a limit of 16384, but I would expect better performance for
    > large file with 64k blocks (and 8k frags).

    The largest block size is 64k, and I have done that as well.

    > If you don't have a need for safety on the files, you could try
    > mount async and measure if it suits better you need for performance than
    > softupdates. Sometimes softupdates is faster, and it is always safer.

    Unfortunately, the files do need a bit of safety.I did think about
    async, but I fear the worst to happen.

    Kristofer
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