← NAS & RAID Calculator

NAS pSEO Landing

2x 10TB RAID 1 NAS Calculator | Usable TB

Estimate usable TB, parity overhead, and fault tolerance for 2x 10TB in RAID 1. Includes reserve planning for NAS and homelab arrays.

Capacity Snapshot

Raw Capacity

20.00 TB

Usable Capacity

9.00 TB

Fault Tolerance

1 drives*

Efficiency

50.0%

Strong redundancy but low capacity efficiency. Great for small, critical datasets. This scenario applies a 10% filesystem reserve.

Run Interactive Calculator →

Alternative Mode Comparison

Mode Usable Tolerance Efficiency
RAID 5 N/A N/A N/A
RAID 6 N/A N/A N/A
RAID 10 N/A N/A N/A
RAID-Z1 N/A N/A N/A
RAID-Z2 N/A N/A N/A

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: 2x 8TB RAID 1 NAS Calculator | Usable TB Next: 2x 12TB RAID 1 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.

How much real-world usable storage does 2x 10TB RAID 1 provide?

This NAS planning scenario estimates 9.00 TB usable after a 10% reserve from 20.00 TB raw.

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 2-drive plan for storage headroom 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.