NAS pSEO Landing
Estimate usable TB, parity overhead, and fault tolerance for 4x 14TB in RAID 6. Includes reserve planning for NAS and homelab arrays.
Raw Capacity
56.00 TB
Usable Capacity
25.20 TB
Fault Tolerance
2 drives
Efficiency
50.0%
Safer for larger arrays with dual parity, at the cost of one extra parity disk. This scenario applies a 10% filesystem reserve.
Run Interactive Calculator →| Mode | Usable | Tolerance | Efficiency |
|---|---|---|---|
| RAID 5 | 37.80 TB | 1 drive | 75.0% |
| RAID 6 | 25.20 TB | 2 drives | 50.0% |
| RAID 10 | 25.20 TB | 1 drive per mirror pair* | 50.0% |
| RAID-Z1 | 37.80 TB | 1 drive | 75.0% |
| RAID-Z2 | 25.20 TB | 2 drives | 50.0% |
This NAS planning scenario estimates 25.20 TB usable after a 10% reserve from 56.00 TB raw.
Keeping free space improves filesystem behavior for snapshots, metadata, and write performance. Full arrays often perform worse and rebuild more slowly.
This setup can tolerate 2 drives. Real-world survivability depends on mirror placement, rebuild stress, and drive health.
It can be practical, but larger drives increase rebuild windows. Validate parity choice and backup policy before committing to the final layout.