Re: Performance of ext4

Holger Kiehl
2008-06-20T08:10:24Z

On Thu, 19 Jun 2008, Theodore Tso wrote:

> On Tue, Jun 17, 2008 at 11:42:36AM +0000, Holger Kiehl wrote:
>> Note how the size of file results.24033.helena.dwd.de changes from
>> 9230 before the test to 8208 bytes after the test. Also note the
>> date both have the same timestamp "2008-06-17 04:35". I have made a
>> copy of results.24033.helena.dwd.de before the test and compared it
>> with that after the test. The file is just truncated by 1022 bytes
>> and there is no garbage.
>
> So the corruption is always a truncation, correct?
>
Correct.

> Did you notice the problem with ext4 w/o the patch queue?
>
No, without patch queue it I did not not notice the problem.

> I have a
> suspicion that the problem may have been introduced by the delayed
> allocation code, but I don't have hard evidence. When you rerun your
> benchmark (which seems to be the closest thing we have to a
> reproduction case), it would be interesting to know if the problem
> goes away with -o nodelalloc (again, it would localize where we need
> to look).
>
Ok I will do thats soon as I have a system available.

Holger