On Mon, Oct 24, 2005 at 04:19:30PM -0400, Joshua Baker-LePain wrote: > On Mon, 24 Oct 2005 at 8:05pm, Arjan van de Ven wrote > > >did you set the journalling mode to write-back? > >The default ext3 journalling mode is more strict than the XFS one, but > >slower (so the trade off is data integrity vs speed); XFS is more > >comparable with the writeback type. The performance difference is mostly > >visible on new file creation... > > > First off, I'd like to apologize for the subject line. It's been a bad > few days, but that's no excuse to start a thread out like that. *sigh* > > Thanks for the suggestions. I tested with 3 different sets of my "tweak > settings", and setting 'data=writeback' actually slowed things down (if it > had any effect). > > Also, to answer the question about versions, all ext3 testing was done > with 2.6.9-11.ELsmp, and all XFS testing was done with > 2.6.9-11.106.unsupportedsmp (centosplus) -- the box is essentialy at U1. > And I'm using bonnie++-1.03a. > > If there are any more suggestions/tweaks/patches, I'd love to hear 'em. > Thanks again. With 3ware cards i get slightly better results (for our workload) in RHEL4 with the following settings: vm.dirty_expire_centisecs = 1000 vm.dirty_writeback_centisecs = 500 vm.dirty_ratio = 5 vm.dirty_background_ratio = 10 Have you tried the kernel in the following bugzilla? I didn't had the time to test it but it seems promising. https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=156437 (Writing large file to 1TB ext3 volume sometimes very slow) You might also want to monitor this bugzilla entry if anyone finds out whats wrong with ext3 ad 3ware cards it will show up there: https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=121434 (Extremely high iowait with 3Ware array and moderate disk activity) Kostas Georgiou
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