On Tue, 9 Feb 2010, Felix Buenemann wrote:
Well to make things short: Using JBOD + ZFS Striped Mirrors vs. controller's RAID10, dropped the max. sequential read I/O from over 400 MByte/s to below 300 MByte/s. However random I/O and sequential writes seemed to perform
Much of the difference is likely that your controller implements true RAID10 wereas ZFS "striped" mirrors are actually load-shared mirrors. Since zfs does not use true striping across vdevs, it relies on sequential prefetch requests to get the sequential read rate up. Sometimes zfs's prefetch is not aggressive enough.
I have observed that there may still be considerably more read performance available (to another program/thread) even while a benchmark program is reading sequentially as fast as it can.
Try running two copies of your benchmark program at once and see what happens.
Bob -- Bob Friesenhahn bfrie...@simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/ GraphicsMagick Maintainer, http://www.GraphicsMagick.org/ _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
