Messages in this thread |  | | | From | Bill Davidsen <> | | Subject | Re: Linux 2.6.29 | | Date | Mon, 30 Mar 2009 15:02:44 -0400 |
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Andreas T.Auer wrote: > 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.
> 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. > Here I have the same question, I don't expect or demand that anything be done in a particular order unless I force it so, and I expect there to be some corner case where the data is written and the metadata doesn't reflect that in the event of a failure, but I can't see that it ever a good idea to have the metadata reflect the future and describe what things will look like if everything goes as planned. I have had enough of that BS from financial planners and politicians, metadata shouldn't try to predict the future just to save a ms here or there. It's also necessary to have the metadata match reality after fsync(), of course, or even the well behaved applications mentioned in this thread haven't a hope of staying consistent.
Feel free to clarify why clairvoyant metadata is ever a good thing...
-- Bill Davidsen <davidsen@tmr.com> "We have more to fear from the bungling of the incompetent than from the machinations of the wicked." - from Slashdot
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