NAS pSEO Landing
Estimate usable TB, parity overhead, and fault tolerance for 10x 4TB in RAID 10. Includes reserve planning for NAS and homelab arrays.
Raw Capacity
40.00 TB
Usable Capacity
18.00 TB
Fault Tolerance
1 drive per mirror pair*
Efficiency
50.0%
Excellent random I/O and rebuild behavior; capacity is typically 50% of raw. This scenario applies a 10% filesystem reserve.
Run Interactive Calculator →| Mode | Usable | Tolerance | Efficiency |
|---|---|---|---|
| RAID 5 | 32.40 TB | 1 drive | 90.0% |
| RAID 6 | 28.80 TB | 2 drives | 80.0% |
| RAID 10 | 18.00 TB | 1 drive per mirror pair* | 50.0% |
| RAID-Z1 | 32.40 TB | 1 drive | 90.0% |
| RAID-Z2 | 28.80 TB | 2 drives | 80.0% |
No. Use this page for pre-purchase sizing, then validate with workload benchmarks, SMART health policy, and a tested restore plan.
This setup can tolerate 1 drive per mirror pair*. Real-world survivability depends on mirror placement, rebuild stress, and drive health.
Keeping free space improves filesystem behavior for snapshots, metadata, and write performance. Full arrays often perform worse and rebuild more slowly.
It can be practical, but larger drives increase rebuild windows. Validate parity choice and backup policy before committing to the final layout.