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Region Focus · UK

UK 10x 20TB RAID 5 NAS Calculator

Estimate usable TB, parity, and fault tolerance for UK homelab buyers using 10x 20TB in RAID 5.

Capacity Snapshot

Raw Capacity

200.00 TB

Usable Capacity

162.00 TB

Fault Tolerance

1 drive

Efficiency

90.0%

Balanced capacity and redundancy, but rebuild stress can be high on large disks. This scenario applies a 10% filesystem reserve.

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Alternative Mode Comparison

Mode Usable Tolerance Efficiency
RAID 5 162.00 TB 1 drive 90.0%
RAID 6 144.00 TB 2 drives 80.0%
RAID 10 90.00 TB 1 drive per mirror pair* 50.0%
RAID-Z1 162.00 TB 1 drive 90.0%
RAID-Z2 144.00 TB 2 drives 80.0%

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.

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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 much real-world usable storage does 10x 20TB RAID 5 provide?

For UK homelab buyers, this NAS planning scenario estimates 162.00 TB usable after a 10% reserve from 200.00 TB raw.

How many disk failures can RAID 5 tolerate in this setup?

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

Is RAID 5 still viable 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.

Should I optimize this 10-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.