NAS pSEO Landing
Estimate usable TB, parity overhead, and fault tolerance for 5x 12TB in RAID-Z2. Includes reserve planning for NAS and homelab arrays.
Raw Capacity
60.00 TB
Usable Capacity
32.40 TB
Fault Tolerance
2 drives
Efficiency
60.0%
Popular TrueNAS default for medium arrays; dual-parity with good safety margin. This scenario applies a 10% filesystem reserve.
Run Interactive Calculator →| Mode | Usable | Tolerance | Efficiency |
|---|---|---|---|
| RAID 5 | 43.20 TB | 1 drive | 80.0% |
| RAID 6 | 32.40 TB | 2 drives | 60.0% |
| RAID 10 | N/A | N/A | N/A |
| RAID-Z1 | 43.20 TB | 1 drive | 80.0% |
| RAID-Z2 | 32.40 TB | 2 drives | 60.0% |
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.
This NAS planning scenario estimates 32.40 TB usable after a 10% reserve from 60.00 TB raw.
No. Use this page for pre-purchase sizing, then validate with workload benchmarks, SMART health policy, and a tested restore plan.