NAS pSEO Landing
Estimate usable TB, parity overhead, and fault tolerance for 12x 18TB in RAID-Z1. Includes reserve planning for NAS and homelab arrays.
Raw Capacity
216.00 TB
Usable Capacity
178.20 TB
Fault Tolerance
1 drive
Efficiency
91.7%
ZFS single-parity equivalent of RAID 5; common for smaller homelab pools. This scenario applies a 10% filesystem reserve.
Run Interactive Calculator →| Mode | Usable | Tolerance | Efficiency |
|---|---|---|---|
| RAID 5 | 178.20 TB | 1 drive | 91.7% |
| RAID 6 | 162.00 TB | 2 drives | 83.3% |
| RAID 10 | 97.20 TB | 1 drive per mirror pair* | 50.0% |
| RAID-Z1 | 178.20 TB | 1 drive | 91.7% |
| RAID-Z2 | 162.00 TB | 2 drives | 83.3% |
This NAS planning scenario estimates 178.20 TB usable after a 10% reserve from 216.00 TB raw.
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.