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6x 8TB RAID 6 NAS Calculator | Usable TB

Estimate usable TB, parity overhead, and fault tolerance for 6x 8TB in RAID 6. Includes reserve planning for NAS and homelab arrays.

Capacity Snapshot

Raw Capacity

48.00 TB

Usable Capacity

28.80 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.

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Alternative Mode Comparison

Mode Usable Tolerance Efficiency
RAID 5 36.00 TB 1 drive 83.3%
RAID 6 28.80 TB 2 drives 66.7%
RAID 10 21.60 TB 1 drive per mirror pair* 50.0%
RAID-Z1 36.00 TB 1 drive 83.3%
RAID-Z2 28.80 TB 2 drives 66.7%

NAS Cluster Guides

NAS Hub RAID Level Compare RAID Capacity Matrix Planning Quick Sheet RAID Selector NAS FAQ

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Sequential Long-Tail Navigation

← Previous: 6x 8TB RAID 5 NAS Calculator | Usable TB Next: 6x 8TB RAID 10 NAS Calculator | Usable TB →

FAQ

Why include a 10% reserve when planning NAS storage headroom?

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

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.

How many disk failures can RAID 6 tolerate in this setup?

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

How much usable storage does 6x 8TB RAID 6 provide?

This NAS planning scenario estimates 28.80 TB usable after a 10% reserve from 48.00 TB raw.