Level 0: striped disk array without fault tolerance
Level 1: mirroring and duplexing
Level 2: error-correcting coding
Level 3: bit-interleaved parity
Level 4: dedicated parity drive
Level 5: block interleaved distributed parity
Level 6: independent data disks with double parity
Level 10: a stripe of mirrors
Some devices use more than one level in a hybrid or nested arrangement, and some vendors also offer non-standard proprietary RAID levels.