raidz3
also: RAID-Z3, ZFS raidz3
A RAID variant in ZFS that uses three-way parity, allowing a storage pool to survive the simultaneous failure of any three drives without data loss.
raidz3 is an advanced RAID implementation in the ZFS filesystem that distributes data and three independent parity blocks across multiple drives. Unlike traditional RAID-6 (which handles only two drive failures), raidz3 can tolerate the failure of up to three drives simultaneously while maintaining data integrity.
The parity is calculated using the RAID-Z algorithm with three parity schemes, spread across the vdev (virtual device). If any three drives fail, the data can be reconstructed from the remaining drives and parity information.
Example: In a raidz3 pool with 8 drives, you lose 3 drives worth of capacity to parity but gain exceptional fault tolerance. If drives 2, 5, and 7 fail, the pool remains online and data is fully recoverable.
raidz3 is ideal for large storage deployments where the risk of multiple simultaneous drive failures increases with array size, though it requires more parity overhead than raidz1 or raidz2.