NAS pSEO Landing
Region Focus · UK
Estimate usable capacity, fault tolerance, and efficiency for UK homelab buyers using 6x 12TB in RAID-Z2.
Raw Capacity
72.00 TB
Usable Capacity
43.20 TB
Fault Tolerance
2 drives
Efficiency
66.7%
Popular TrueNAS default for medium arrays; dual-parity with good safety margin. This scenario applies a 10% filesystem reserve.
Run Interactive Calculator →| Mode | Usable | Tolerance | Efficiency |
|---|---|---|---|
| RAID 5 | 54.00 TB | 1 drive | 83.3% |
| RAID 6 | 43.20 TB | 2 drives | 66.7% |
| RAID 10 | 32.40 TB | 1 drive per mirror pair* | 50.0% |
| RAID-Z1 | 54.00 TB | 1 drive | 83.3% |
| RAID-Z2 | 43.20 TB | 2 drives | 66.7% |
UK homelab planners commonly balance higher per-drive pricing with power and chassis constraints, so efficient but resilient layouts become more valuable.
Expected always-on energy usage cost factored into NAS layout decisions.
Estimated time exposure while replacing a failed drive and restoring parity.
For UK homelab buyers, this NAS planning scenario estimates 43.20 TB usable after a 10% reserve from 72.00 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.
Keeping free space improves filesystem behavior for snapshots, metadata, and write performance. Full arrays often perform worse and rebuild more slowly.
This setup can tolerate 2 drives. Real-world survivability depends on mirror placement, rebuild stress, and drive health.