On Mon, Aug 02, 2010 at 11:03:00PM +0400, Vladislav Bolkhovitin wrote: > I traced what XFS is doing that time. The initiator is sending by a _single command at time_ the following pattern: That's exactly the queue draining we're talking about here. To see how the pattern gets better use the nobarrier option. Even with that XFS traditionally has a bad I/O pattern for metadata intensive workloads due to the amount of log I/O needed for it. Starting from Linux 2.6.35 the delayed logging code fixes this, and we hope to enable it by default after about 10 to 12 month of extensive testing. Try to re-run your test with -o delaylog,logbsize=262144 to see better log I/O pattern. If you target doesn't present a volatile write cache also add the nobarrier option mentioned above. -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
