On Jan 14, 2010, at 3:59 PM, Ray Van Dolson wrote: > On Thu, Jan 14, 2010 at 03:55:20PM -0800, Ray Van Dolson wrote: >> On Thu, Jan 14, 2010 at 03:41:17PM -0800, Richard Elling wrote: >>>> Consider a pool of 3x 2TB SATA disks in RAIZ1, you would roughly >>>> have 80 IOPS. Any info about the relation between ZIL <> pool >>>> performance? Or will the ZIL simply fill up and performance drops >>>> to pool speed? >>> >>> The ZFS write performance for this configuration should consistently >>> be greater than 80 IOPS. We've seen measurements in the 600 write >>> IOPS range. Why? Because ZFS writes tend to be contiguous. Also, >>> with the SATA disk write cache enabled, bursts of writes are handled >>> quite nicely. >>> -- richard >> >> That's interesting. I was under the impression that your IOPS for a >> zpool were limited to the slowest drive in a vdev -- times the number >> of vdevs. >> > > Qualification: For RAIDZ*
That is a simple performance model for small, random reads. The ZIL is a write-only workload, so the model will not apply. -- richard _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
