RAID Levels Explained: RAID 0, 1, 5, 6 and 10
RAID combines multiple drives into a storage array. Depending on the selected level, RAID can improve performance, provide redundancy or combine both features.
What Does RAID Mean?
RAID stands for Redundant Array of Independent Disks. A RAID controller or software system manages several drives as one logical storage system.
Important: RAID is not a backup. RAID can help a server continue operating after a drive failure, but it does not protect against accidental deletion, malware, theft, fire or serious hardware damage.
Common RAID Levels
| RAID level | Minimum drives | Main benefit | Drive failure protection |
|---|---|---|---|
| RAID 0 | 2 | High performance and full combined capacity | None |
| RAID 1 | 2 | Mirrored data | One drive in a mirror |
| RAID 5 | 3 | Capacity with single-drive parity protection | One drive |
| RAID 6 | 4 | Dual parity protection | Two drives |
| RAID 10 | 4 | Mirroring combined with striping | Depends on which drives fail |
RAID 0
RAID 0 divides data across multiple drives. It can provide high performance, but one failed drive can cause the entire array to become unusable.
RAID 1
RAID 1 mirrors the same data onto two drives. If one drive fails, the remaining drive can continue operating while the failed drive is replaced.
RAID 5 and RAID 6
RAID 5 uses parity information to protect against one drive failure. RAID 6 uses additional parity and can protect against two failed drives.
