RAID Level Quick Reference
| Level | Min Disks | Fault Tolerance | Use Case |
|---|---|---|---|
| RAID 0 | 1 | None | Max throughput, no redundancy (scratch/temp) |
| RAID 1 | 2 | n−1 disks | Boot volumes, critical small datasets |
| RAID 5 | 3 | 1 disk | General-purpose, good balance of capacity & protection |
| RAID 6 | 4 | 2 disks | Large drives (>4 TB) where rebuild risk is high |
| RAID 10 | 4 (even) | ≥1 disk per pair | Databases, best IOPS + redundancy |
| RAID 50 | 6 | 1 per group | Large arrays needing performance + parity |
| RAID 60 | 8 | 2 per group | Very large arrays, maximum durability |
About this tool
RAID (Redundant Array of Independent Disks) trades raw capacity for fault tolerance and/or performance. The key metric for planning is usable capacity - how much you can actually store - versus the raw total of all drives. RAID 5 is popular for its efficiency (only 1 disk of overhead) but becomes risky with large drives because rebuild times can exceed 24 hours, increasing the window for a second failure. RAID 6 mitigates this with double-parity. For database workloads requiring maximum IOPS, RAID 10 is typically preferred despite its 50% efficiency. RAID 50 and RAID 60 are nested levels suited to large JBODs and enterprise SAN arrays.