NAS pSEO Landing
Estimate usable TB, parity overhead, and fault tolerance for 12x 20TB in RAID 6. Includes reserve planning for NAS and homelab arrays.
Raw Capacity
240.00 TB
Usable Capacity
180.00 TB
Fault Tolerance
2 drives
Efficiency
83.3%
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 | 198.00 TB | 1 drive | 91.7% |
| RAID 6 | 180.00 TB | 2 drives | 83.3% |
| RAID 10 | 108.00 TB | 1 drive per mirror pair* | 50.0% |
| RAID-Z1 | 198.00 TB | 1 drive | 91.7% |
| RAID-Z2 | 180.00 TB | 2 drives | 83.3% |
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.
This NAS planning scenario estimates 180.00 TB usable after a 10% reserve from 240.00 TB raw.
It can be practical, but larger drives increase rebuild windows. Validate parity choice and backup policy before committing to the final layout.