EU 6x 20TB RAID 6 NAS Calculator

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

Capacity Snapshot

Raw Capacity

120.00 TB

Usable Capacity

72.00 TB

Fault Tolerance

2 drives

Efficiency

66.7%

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	90.00 TB	1 drive	83.3%
RAID 6	72.00 TB	2 drives	66.7%
RAID 10	54.00 TB	1 drive per mirror pair*	50.0%
RAID-Z1	90.00 TB	1 drive	83.3%
RAID-Z2	72.00 TB	2 drives	66.7%

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.

For EU homelab buyers, this NAS planning scenario estimates 72.00 TB usable after a 10% reserve from 120.00 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.

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