EU 10x 12TB RAID 10 NAS Calculator

Estimate usable TB, parity, and fault tolerance for EU homelab buyers using 10x 12TB in RAID 10.

Capacity Snapshot

Raw Capacity

120.00 TB

Usable Capacity

54.00 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.

Mode	Usable	Tolerance	Efficiency
RAID 5	97.20 TB	1 drive	90.0%
RAID 6	86.40 TB	2 drives	80.0%
RAID 10	54.00 TB	1 drive per mirror pair*	50.0%
RAID-Z1	97.20 TB	1 drive	90.0%
RAID-Z2	86.40 TB	2 drives	80.0%

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.

For long-lived NAS pools, resiliency first is usually safer. Capacity can be expanded later, while a risky parity choice can force migration sooner.

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 54.00 TB usable after a 10% reserve from 120.00 TB raw.

This setup can tolerate 1 drive per mirror pair*. Real-world survivability depends on mirror placement, rebuild stress, and drive health.