NAS pSEO Landing
Estimate usable TB, parity overhead, and fault tolerance for 6x 4TB in RAID-Z1. Includes reserve planning for NAS and homelab arrays.
Raw Capacity
24.00 TB
Usable Capacity
18.00 TB
Fault Tolerance
1 drive
Efficiency
83.3%
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 | 18.00 TB | 1 drive | 83.3% |
| RAID 6 | 14.40 TB | 2 drives | 66.7% |
| RAID 10 | 10.80 TB | 1 drive per mirror pair* | 50.0% |
| RAID-Z1 | 18.00 TB | 1 drive | 83.3% |
| RAID-Z2 | 14.40 TB | 2 drives | 66.7% |
For long-lived NAS pools, resiliency first is usually safer. Capacity can be expanded later, while a risky parity choice can force migration sooner.
This NAS planning scenario estimates 18.00 TB usable after a 10% reserve from 24.00 TB raw.
This setup can tolerate 1 drive. Real-world survivability depends on mirror placement, rebuild stress, and drive health.
No. Use this page for pre-purchase sizing, then validate with workload benchmarks, SMART health policy, and a tested restore plan.