Solaris ZFS Administration Guide

Double Parity RAID-Z (raidz2)

Solaris Express Community Release, build 42: A redundant RAID-Z configuration can now have either single- or double-parity, which means that one or two device failures can be sustained respectively, without any data loss. You can specify the raidz2 keyword for a double-parity RAID-Z configuration. Or, you can specify the raidz or raidz1 keyword for a single-parity RAID-Z configuration.

For more information, see Creating RAID-Z Storage Pools or zpool(1M).