EU 8x 20TB RAID 6 NAS Calculator

Estimate usable TB, parity, and fault tolerance for EU homelab buyers using 8x 20TB in RAID 6.

Capacity Snapshot

Raw Capacity

160.00 TB

Usable Capacity

108.00 TB

Fault Tolerance

2 drives

Efficiency

75.0%

Safer for larger arrays with dual parity, at the cost of one extra parity disk. This scenario applies a 10% filesystem reserve.

Mode	Usable	Tolerance	Efficiency
RAID 5	126.00 TB	1 drive	87.5%
RAID 6	108.00 TB	2 drives	75.0%
RAID 10	72.00 TB	1 drive per mirror pair*	50.0%
RAID-Z1	126.00 TB	1 drive	87.5%
RAID-Z2	108.00 TB	2 drives	75.0%

EU deployments often place additional emphasis on energy efficiency and predictable lifecycle upgrades, especially for always-on NAS fleets.

• Choose a layout that minimizes emergency rebuild risk under continuous operation.
• Prefer capacity plans that survive one upgrade cycle without pool redesign.

Capacity and reliability strategy across multiple hardware refresh cycles.

Intentional free-space margin to protect performance and snapshot behavior.

This setup can tolerate 2 drives. 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.

It can be practical, but larger drives increase rebuild windows. Validate parity choice and backup policy before committing to the final layout.

For EU homelab buyers, this NAS planning scenario estimates 108.00 TB usable after a 10% reserve from 160.00 TB raw.