Storage · 2026-11-14
RAID levels explained for business: RAID 1, 5, 6 and 10
What each RAID level protects against, how much capacity you lose, and which to use for NAS, file servers and databases.
RAID combines several drives into one volume to add speed, redundancy or both. It protects against a drive failing; it is not a backup.
| Level | Minimum drives | Survives | Usable capacity | Typical use |
|---|---|---|---|---|
| RAID 0 | 2 | No failures | 100% | Scratch space only |
| RAID 1 | 2 | 1 drive | 50% | Boot volumes, 2-bay NAS |
| RAID 5 | 3 | 1 drive | (n-1)/n | Small NAS, general file storage |
| RAID 6 | 4 | 2 drives | (n-2)/n | Large-capacity arrays, backup targets |
| RAID 10 | 4 | 1 per mirror pair | 50% | Databases, virtual machines |
Choosing
- Large drives (8 TB and up): prefer RAID 6. Rebuilding a RAID 5 array with large drives takes many hours, during which a second failure loses everything.
- Performance-sensitive workloads: RAID 10 on SSDs or 10K SAS drives.
- Synology SHR and QNAP equivalents: flexible versions of RAID 5/6 that allow mixed drive sizes.
- Hot spares: keep one in arrays of six or more drives so rebuilds start immediately.
Use our RAID calculator to see usable capacity for your drive count, then browse NAS and enterprise drives.
Request a quote or message us on WhatsApp and we will help you choose.
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