On Wed, Jan 6, 2010 at 4:30 PM, Wes Felter <wes...@felter.org> wrote: > Michael Herf wrote: > >> I agree that RAID-DP is much more scalable for reads than RAIDZx, and >> this basically turns into a cost concern at scale. >> >> The raw cost/GB for ZFS is much lower, so even a 3-way mirror could be >> used instead of netapp. But this certainly reduces the cost advantage >> significantly. > > Has anyone compared RAID-Z2 against something like LSI MegaRAID RAID-6? If a > sub-$1,000 RAID controller can save thousands of dollars worth of disks it > would somewhat put the lie to the idea that ZFS kills hardware RAID.
A hardware RAID6 controller with a big battery backed write cache will beat RAIDZ2 hands down. It avoids the write-hole problem with the battery cache, but you still have the possibility of silent data corruption to deal with. You could put two LSI MegaRAID controllers into a 2U box each going to a storage enclosure setup with a RAID6 array, then setup a zpool made out of a mirrored vdev of each. That takes RAIDZ2 out of the picture while providing integrity and performance. Extra cost is always assumed if you want both. If you want to add redundancy it will cost you double. -Ross _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
