NAS pSEO Landing
Estimate usable TB, parity overhead, and fault tolerance for 4x 16TB in RAID 6. Includes reserve planning for NAS and homelab arrays.
Raw Capacity
64.00 TB
Usable Capacity
28.80 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 | 43.20 TB | 1 drive | 75.0% |
| RAID 6 | 28.80 TB | 2 drives | 50.0% |
| RAID 10 | 28.80 TB | 1 drive per mirror pair* | 50.0% |
| RAID-Z1 | 43.20 TB | 1 drive | 75.0% |
| RAID-Z2 | 28.80 TB | 2 drives | 50.0% |
This NAS planning scenario estimates 28.80 TB usable after a 10% reserve from 64.00 TB raw.
It can be practical, but larger drives increase rebuild windows. Validate parity choice and backup policy before committing to the final layout.
For long-lived NAS pools, resiliency first is usually safer. Capacity can be expanded later, while a risky parity choice can force migration sooner.
This setup can tolerate 2 drives. Real-world survivability depends on mirror placement, rebuild stress, and drive health.