NAS pSEO Landing

10x 20TB RAID 6 NAS Calculator | Usable TB

Estimate usable TB, parity overhead, and fault tolerance for 10x 20TB in RAID 6. Includes reserve planning for NAS and homelab arrays.

Capacity Snapshot

Raw Capacity

200.00 TB

Usable Capacity

144.00 TB

Fault Tolerance

2 drives

Efficiency

80.0%

Safer for larger arrays with dual parity, at the cost of one extra parity disk. This scenario applies a 10% filesystem reserve.

Run Interactive Calculator →

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%

NAS Cluster Guides

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

Related Long-Tail Calculators

2x 4TB RAID 1 2x 6TB RAID 1 2x 8TB RAID 1 2x 10TB RAID 1 2x 12TB RAID 1 2x 14TB RAID 1 2x 16TB RAID 1 2x 18TB RAID 1 2x 20TB RAID 1 3x 4TB RAID 1 3x 4TB RAID 5 3x 4TB RAID-Z1 3x 6TB RAID 1 3x 6TB RAID 5 3x 6TB RAID-Z1 3x 8TB RAID 1

Sequential Long-Tail Navigation

← Previous: 10x 20TB RAID 5 NAS Calculator | Usable TB Next: 10x 20TB RAID 10 NAS Calculator | Usable TB →

FAQ

Is RAID 6 still practical 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.

How much effective storage does 10x 20TB RAID 6 provide?

This NAS planning scenario estimates 144.00 TB usable after a 10% reserve from 200.00 TB raw.

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.

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.