NAS & RAID Calculator

NAS pSEO Landing

4x 4TB RAID 10 NAS Calculator | Usable TB

Estimate usable TB, parity overhead, and fault tolerance for 4x 4TB in RAID 10. Includes reserve planning for NAS and homelab arrays.

Capacity Snapshot

Raw Capacity

16.00 TB

Usable Capacity

7.20 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.

Run Interactive Calculator

Alternative Mode Comparison

Mode Usable Tolerance Efficiency
RAID 5 10.80 TB 1 drive 75.0%
RAID 6 7.20 TB 2 drives 50.0%
RAID 10 7.20 TB 1 drive per mirror pair* 50.0%
RAID-Z1 10.80 TB 1 drive 75.0%
RAID-Z2 7.20 TB 2 drives 50.0%

NAS Cluster Guides

Related Long-Tail Calculators

Sequential Long-Tail Navigation

FAQ

How much real-world usable storage does 4x 4TB RAID 10 provide?

This NAS planning scenario estimates 7.20 TB usable after a 10% reserve from 16.00 TB raw.

Should I optimize this 4-drive plan for capacity 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 viable with 4TB drives?

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

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.