NAS & RAID Calculator

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Region Focus · UK

UK 6x 20TB RAID 10 NAS Calculator

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

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Alternative Mode Comparison

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%

UK Buyer Context

UK homelab planners commonly balance higher per-drive pricing with power and chassis constraints, so efficient but resilient layouts become more valuable.

Brand / Region Glossary

Power Budget

Expected always-on energy usage cost factored into NAS layout decisions.

Rebuild Window

Estimated time exposure while replacing a failed drive and restoring parity.

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FAQ

How many disk failures can RAID 10 tolerate in this setup?

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

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.

Should I optimize this 6-drive plan for available space or resiliency first?

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

Is RAID 10 still worth deploying with 20TB drives?

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