> On Nov 7, 2013, at 10:23 AM, tclug at freakzilla.com wrote: > > It's a raidz2 array, so 6 disks for data and 2 disks for spares. Can you help me understand the point of hot spares with ZFS? (Cold spares save energy, I get that. ) Or, do you mean 6 disks' worth of useful data & 2 disks being used for parity data? ZFS doesn't use whole parity drives. "Unlike RAID-5, RAID-Z doesn't use one specific drive for the parity, but it rotates the parity around different disks. This makes the system more efficient and prevents the parity disk from wearing out as fast." http://superuser.com/questions/255783/zfs-raidz-parity See here for an example of how hot spares might not be useful: https://blogs.oracle.com/ahl/entry/triple_parity_raid_z#comment-1248937070000 Thomas