NAS pSEO Landing
Estimate usable TB, parity overhead, and fault tolerance for 8x 10TB in RAID-Z2. Includes reserve planning for NAS and homelab arrays.
Raw Capacity
80.00 TB
Usable Capacity
54.00 TB
Fault Tolerance
2 drives
Efficiency
75.0%
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 | 63.00 TB | 1 drive | 87.5% |
| RAID 6 | 54.00 TB | 2 drives | 75.0% |
| RAID 10 | 36.00 TB | 1 drive per mirror pair* | 50.0% |
| RAID-Z1 | 63.00 TB | 1 drive | 87.5% |
| RAID-Z2 | 54.00 TB | 2 drives | 75.0% |
This setup can tolerate 2 drives. Real-world survivability depends on mirror placement, rebuild stress, and drive health.
This NAS planning scenario estimates 54.00 TB usable after a 10% reserve from 80.00 TB raw.
No. Use this page for pre-purchase sizing, then validate with workload benchmarks, SMART health policy, and a tested restore plan.
It can be practical, but larger drives increase rebuild windows. Validate parity choice and backup policy before committing to the final layout.