What is RAID?
RAID stands for Redundant Array of Independent Disks. Imagine a group of friends carrying books. Together they can carry more, or they can each hold a copy so nothing is lost if one drops a book. RAID uses two main tricks.
- Striping: data is split across drives. This makes reading and writing faster.
- Mirroring: the same data is written to two drives. If one dies, the other still has everything.
- Parity: extra checking information. It lets the group rebuild lost data after a drive fails.
The common levels
| Level | Drives needed | What it does | If a drive fails |
|---|---|---|---|
| RAID 0 | 2 or more | Striping only. Fastest, no safety. | All data is lost |
| RAID 1 | 2 | Mirroring. Two copies. | Data is safe |
| RAID 5 | 3 or more | Striping plus parity. | Survives 1 failure |
| RAID 6 | 4 or more | Striping plus double parity. | Survives 2 failures |
| RAID 10 | 4 or more | Mirrors that are then striped. | Usually survives one failure per pair |
Which one to choose
- Pick RAID 0 only for temporary data that you can lose, where speed matters most.
- Pick RAID 1 for a simple, safe setup with two drives.
- Pick RAID 5 or 6 to get more usable space while keeping some safety.
- Pick RAID 10 for busy databases that need both speed and safety.
An important warning
RAID is not a backup. If you delete a file by mistake, RAID deletes it everywhere. If a virus hits your site, every copy is hit. RAID protects against a broken drive only. Always keep separate backups too.
Tip: Want to know which RAID your VPS or dedicated server uses? Ask Hostvento support through a ticket at https://secure.hostvento.com/submitticket.php.
Quick recap
- RAID combines drives for speed, safety or both.
- RAID 0 is fast but risky. RAID 1 mirrors. RAID 5 and 6 use parity. RAID 10 mixes mirroring and striping.
- RAID is not a backup.