Calculate usable capacity, fault tolerance, and rebuild characteristics across RAID 0, 1, 5, 6, 10, 50, and 60. Sizes update live as you type.
RAID (Redundant Array of Independent Disks) combines multiple physical drives into logical units for performance, redundancy, or both. The trade-off is between usable capacity, fault tolerance, and rebuild risk.
| RAID | Min drives | Fault tolerance | Efficiency | Best for |
|---|---|---|---|---|
| 0 | 2 | None | 100% | Scratch / cache |
| 1 | 2 | 1 drive | 50% | OS boot drives |
| 5 | 3 | 1 drive | (N-1)/N | General purpose, file servers |
| 6 | 4 | 2 drives | (N-2)/N | Large arrays, archive, backups |
| 10 | 4 (even) | 1 per mirror | 50% | Databases, VMs, performance |
| 50 | 6 | 1 per sub-array | ~83–93% | Large, performance-critical arrays |
| 60 | 8 | 2 per sub-array | ~67–87% | Very large arrays with safety |
With drives ≥ 4 TB and arrays ≥ 8 drives, RAID 5 carries meaningful risk of a second drive failure during rebuild (which can take 24–72+ hours). For modern large-capacity arrays, RAID 6 or RAID 10 is the safer default. The calculator flags this in the verdict box.
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