NAS & RAID Calculator

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Region Focus · EU

EU 10x 8TB RAID-Z2 NAS Calculator

Estimate usable TB, parity, and fault tolerance for EU homelab buyers using 10x 8TB in RAID-Z2.

Capacity Snapshot

Raw Capacity

80.00 TB

Usable Capacity

57.60 TB

Fault Tolerance

2 drives

Efficiency

80.0%

Popular TrueNAS default for medium arrays; dual-parity with good safety margin. This scenario applies a 10% filesystem reserve.

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Alternative Mode Comparison

Mode Usable Tolerance Efficiency
RAID 5 64.80 TB 1 drive 90.0%
RAID 6 57.60 TB 2 drives 80.0%
RAID 10 36.00 TB 1 drive per mirror pair* 50.0%
RAID-Z1 64.80 TB 1 drive 90.0%
RAID-Z2 57.60 TB 2 drives 80.0%

EU Buyer Context

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

Brand / Region Glossary

Lifecycle Planning

Capacity and reliability strategy across multiple hardware refresh cycles.

Operational Headroom

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

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FAQ

Can this calculator replace real-world benchmark and rebuild testing?

No. Use this page for pre-purchase sizing, then validate with workload benchmarks, SMART health policy, and a tested restore plan.

Why include a 10% reserve when planning NAS available space?

Keeping free space improves filesystem behavior for snapshots, metadata, and write performance. Full arrays often perform worse and rebuild more slowly.

How many disk failures can RAID-Z2 tolerate in this setup?

This setup can tolerate 2 drives. Real-world survivability depends on mirror placement, rebuild stress, and drive health.

Is RAID-Z2 still viable with 8TB drives?

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