raidz1
also: RAID-Z1, raidz
A RAID-Z variant in ZFS that provides single-disk fault tolerance by distributing data and parity across multiple drives, allowing the pool to survive the failure of any one disk.
raidz1 is ZFS's implementation of RAID-5-like protection, distributing data and parity information across a minimum of three drives. If any single drive fails, the remaining drives can reconstruct the lost data using the parity blocks.
It offers a good balance between storage efficiency and fault tolerance—unlike mirroring, you lose only one disk's worth of capacity to parity overhead. For example, a raidz1 vdev with four 1TB drives gives you roughly 3TB of usable space.
The main trade-off is performance during rebuilds: reconstructing a failed disk requires reading and calculating data from all remaining drives, making it slower and more stressful on hardware than mirrored setups.
Example ZFS pool creation: zpool create tank raidz1 /dev/sda /dev/sdb /dev/sdc