5 ms·
It means that the vdev on top of the three RAIDZ vdevs can lose up to three devices simultaneously, one per RAIDZ each. Any further failure would result in a c
by Annatar 10y ago
It means that the vdev on top of the three RAIDZ vdevs can lose up to three devices simultaneously, one per RAIDZ each.
Any further failure would result in a complete data loss. Also, if any of the RAIDZ stripes loses more than one vdev simultaneously, this will lead to a complete data loss as well.
- ewwhite 10y agoThis is a simple example setup in a 12-drive enclosure. 9 disks, a global hot-spare disk and two cache drives. Previously, I would have used straight ZFS mirrors for performance and expandability (raidz VDEVs can't be expanded), but at this scale, the 9-disk 3x3 raidz1 setup consistently outperformed a 10-disk RAID mirror setup in random and sequential I/O. See: http://i.imgur.com/SeSlmH8.png http://i.imgur.com/SeSlmH8.png
- eatstoomuchjam 10y agoA set of 5 stripes of mirrors has the same problem that the comment brought up - losing the _wrong_ two disks loses all of your data. In this case, going to raidz2 across all 12 disks would give an extra disk worth of capacity/performance with the ability to lose any 2 disks without data loss and going to raidz3 should give the same capacity/performance with the ability to lose any 3 disks without data loss.
- ewwhite 10y agoHot spares and monitoring. RaidZ2 across that number of drives is a performance nightmare and against ZFS best practices.