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2x 12TB RAID 1 Calculator

Estimate usable capacity, fault tolerance, and efficiency for 2x 12TB in RAID 1 with reserve best practices.

Capacity Snapshot

Raw Capacity

24.00 TB

Usable Capacity

10.80 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.

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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

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

FAQ

How many disk failures can RAID 1 tolerate in this setup?

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

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.

Is RAID 1 still practical with 12TB 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.