NAS pSEO Landing
Estimate usable TB, parity overhead, and fault tolerance for 6x 18TB in RAID 1. Includes reserve planning for NAS and homelab arrays.
Raw Capacity
108.00 TB
Usable Capacity
16.20 TB
Fault Tolerance
5 drives*
Efficiency
16.7%
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 | 81.00 TB | 1 drive | 83.3% |
| RAID 6 | 64.80 TB | 2 drives | 66.7% |
| RAID 10 | 48.60 TB | 1 drive per mirror pair* | 50.0% |
| RAID-Z1 | 81.00 TB | 1 drive | 83.3% |
| RAID-Z2 | 64.80 TB | 2 drives | 66.7% |
This setup can tolerate 5 drives*. Real-world survivability depends on mirror placement, rebuild stress, and drive health.
For long-lived NAS pools, resiliency first is usually safer. Capacity can be expanded later, while a risky parity choice can force migration sooner.
No. Use this page for pre-purchase sizing, then validate with workload benchmarks, SMART health policy, and a tested restore plan.
Keeping free space improves filesystem behavior for snapshots, metadata, and write performance. Full arrays often perform worse and rebuild more slowly.