NAS pSEO Landing
Estimate usable TB, parity overhead, and fault tolerance for 5x 20TB in RAID 1. Includes reserve planning for NAS and homelab arrays.
Raw Capacity
100.00 TB
Usable Capacity
18.00 TB
Fault Tolerance
4 drives*
Efficiency
20.0%
Strong redundancy but low capacity efficiency. Great for small, critical datasets. This scenario applies a 10% filesystem reserve.
Run Interactive Calculator →| Mode | Usable | Tolerance | Efficiency |
|---|---|---|---|
| RAID 5 | 72.00 TB | 1 drive | 80.0% |
| RAID 6 | 54.00 TB | 2 drives | 60.0% |
| RAID 10 | N/A | N/A | N/A |
| RAID-Z1 | 72.00 TB | 1 drive | 80.0% |
| RAID-Z2 | 54.00 TB | 2 drives | 60.0% |
This NAS planning scenario estimates 18.00 TB usable after a 10% reserve from 100.00 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.
This setup can tolerate 4 drives*. Real-world survivability depends on mirror placement, rebuild stress, and drive health.