Re: Disk I/O Performance

From: Mike Horwath (drechsau_at_geeks.org)
Date: 10/19/04

  • Next message: Kristofer Pettijohn: "Re: Disk I/O Performance" 
    Date: Tue, 19 Oct 2004 15:52:25 -0500
To: João_Carlos_Mendes_Luís <jonny@jonny.eng.br>

    On Tue, Oct 19, 2004 at 04:45:03PM -0300, João_Carlos_Mendes_Luís 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.
    >
    > 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).
    >
    > 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.

    All good ideas except the issue is bandwidth performance across the
    disks.

    I am seeing the same thing (and Kristofer and I have been working
    together, kinda, on this). It is as if I/O is being preferred for
    writing vs reading, very weird.

    His 5 disk stripe (well, it used to be five when I managed the
    machine) should not have issues, but this recently begun happening
    both on his systems and some of mine.

    Very odd stuff... 

    -- 
Mike Horwath, reachable via drechsau@Geeks.ORG
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  • Next message: Kristofer Pettijohn: "Re: Disk I/O Performance"

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    • Re: Disk I/O Performance
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    • Re: Disk I/O Performance
      ... >> I'd say that you have to check which CCD chunk size is best for ... The manual for vinum recommends avoiding chunk sized to a ... > been avoiding powers of 2. ...
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