| RAID Level | Meaning |
| 0 |
Two or more striped disks without redundancy. Improves I/O performance. |
|
1 |
Mirroring of two or more disks. Fault tolerance. |
| 2 | Striping with "Hammering code" parity. Poor performance and expensive. Rarely used. |
| 3 | Striped set of disks with dedicated parity disk (byte level). Parity disk impaires write performance. Fault tolerance, also for parity disk|. |
| 4 | Striped set of disks with dedicated parity disk (block level). Parity disk impaires write performance. Fault tolerance, also for parity disk|. |
| 5 | Striped set of disks with distributed parity. Tolerates loss of one disk. |
| 6 | Striped set of disks with dual distributed parity. Tolerates loss of two disks. |
| 0+1 | Striped sets in a mirrored set |
| 1+0 | Mirrored sets in a striped set |
| 5+0 | Stripe across distributed parity RAID |
| 5+1 |
Striped array whose segments are RAID 3 arrays |