On Fri, Nov 26, 2004 at 03:37:36PM +0100, Daniel Tiefnig wrote: > >What filesystem are you using?
>
> It's ext3.
>
> >If it is a journaling filesystem, and the journal had filled right up
> >and was being flushed to a busy disk subsystem there is a chance
> >that all writes could hang.
>
> I think you got it.
> Watching the cache statistics of the RAID controler, I can see that the
> hangs in the logging appear when the write hits drop down to about 20%
> to 30%. It then goes up to about 70% to 90%, and logging/work continues.
ext3 is a really bad idea for this i have to say.
I'm sure a lot of people find it ok, but for high performance (or even
som medium performance!) ext3 is not the choice. It's approximately half
the speed of the non-journalling ext2.
Filesystems like XFS and Reiser will be much faster.