On Monday 16 July 2007 14:22:25 David Chinner wrote:

You can see from the ext3 graph that it comes to a screeching halt
every 5s (probably when pdflush runs) and at all other times the
seek rate is >10,000 seeks/s. That's pretty bad for a brand new,
empty filesystem and the only way it is sustained is the fact that
the disks have their write caches turned on. ext4 will probably show
better results, but I haven't got any of the tools installed to be
able to test it....

I recently did some filesystem throuput tests, you may find it here

http://www.pci.uni-heidelberg.de/tc/usr/bernd/downloads/lustre/performance/

ldiskfs is ext3+extents+mballoc+some-smaller-patches, so is almost ext4 
(delayed allocation is still missing, but the clusterfs/lustre people didn't 
port it and I'm afraid of hard to detect filesystem corruptions if I include 
it myself).

Write performance is still slower than with xfs and I'm really considering to 
try to use xfs in lustre.

Cheers,
Bernd


-- 
Bernd Schubert
Q-Leap Networks GmbH