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    SubjectRe: Linux 2.6.29

    On 30.03.2009 02:39 Theodore Tso wrote:
    > All I can do is apologize to all other filesystem developers profusely
    > for ext3's data=ordered semantics; at this point, I very much regret
    > that we made data=ordered the default for ext3. But the application
    > writers vastly outnumber us, and realistically we're not going to be
    > able to easily roll back eight years of application writers being
    > trained that fsync() is not necessary, and actually is detrimental for
    > ext3.
    It seems you still didn't get the point. ext3 data=ordered is not the
    problem. The problem is that the average developer doesn't expect the fs
    to _re-order_ stuff. This is how most common fs did work long before
    ext3 has been introduced. They just know that there is a caching and
    they might lose recent data, but they expect the fs on disk to be a
    snapshot of the fs in memory at some time before the crash (except when
    crashing while writing). But the re-ordering brings it to the state that
    never has been in memory. data=ordered is just reflecting this thinking.
    With data=writeback as the default the users would have lost data and
    would have simply chosen a different fs instead of twisting the params.
    Or the distros would have made data=ordered the default to prevent
    beeing blamed for the data loss.

    And still I don't know any reason, why it makes sense to write the
    metadata to non-existing data immediately instead of delaying that, too.

     \ /
      Last update: 2009-03-30 09:15    [W:0.022 / U:2.492 seconds]
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