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    SubjectRe: broken VM in 2.4.10-pre9
    In article <1000722338.14005.0.camel@x153.internalnet>,
    Tonu Samuel <> wrote:
    >Problem still exists and persists. Not long time ago man from Yahoo
    >described well case when change from 2.2.19 to 2.4.x caused performance
    >problems. On 2.2.19 everything ran fine. They have MySQL running+did
    >backups from disk. After upgrade to 2.4.x MySQL performance felt down on
    >backup time. They investigated stuff and found that MySQL daemon gets
    >swapped out in the middle of usage to make room for buffers.

    Note that if you're using a raw device backup strategy (ie "e2dump" or
    similar), that is expected: 2.4.x up until about 2.4.7 gave _much_ too
    much preference to the buffer cache.

    That should actually have been fixed in 2.4.8. We used to mark buffer
    pages much too active.

    > In summary:
    >this made both sql and backup double slow. Even increasing memory from
    >1G->2G didn't helped. Finally they disabled swap at all and problem

    You just hid the problem - by disabling swap the buffer cache couldn't
    grow without bounds any more, and the proper buffer cache shrinking
    couldn't happen.

    Try 2.4.8 or later.

    >If you do not want to change it back as it was in 2.2.x then would be
    >good if this is tunable somehow.

    Tuning for bugs?

    What do you want to happen? You want to have an interface like

    echo 0 > /proc/bugs/mm

    that makes mm bugs go away?

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      Last update: 2005-03-22 13:17    [W:0.094 / U:1.472 seconds]
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