On 20/10/2010 14:03, Edward Ned Harvey wrote:
In a discussion a few weeks back, it was mentioned that the Best Practices Guide says something like "Don't put more than ___ disks into a single vdev." At first, I challenged this idea, because I see no reason why a 21-disk raidz3 would be bad. It seems like a good thing.
If you have those 21 disks spread across 3 top level vdevs each of raidz3 with 7 disks then ZFS can will stripe across 3 vdevs rather than than 1.
Here is an example from the Sun ZFS Storage Appliance GUI: Each O is a score out of 5 ---------------------------------------------------------------------- AVAIL PERF CAPACITY Double parity RAID OOOO_ OOO__ OOOO_ 1.45T Mirrored OOOO_ OOOOO O____ 808G Single partiy RAID, narrow stripes OOO__ OOOO_ OO___ 1.18T Striped _____ OOOOO OOOOO 1.84T Triple mirrored OOOO_ OOOOO _____ 538G Triple parity RAID, wide stripes OOOO_ OO___ OOOOO 1.31T ---------------------------------------------------------------------- -- Darren J Moffat _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss