Re: Performance of ext4

[Theodore Tso <tytso@mit.edu>]

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?

Did you notice the problem with ext4 w/o the patch queue?  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).

Thanks, regards,

						- Ted