NAS & RAID Calculator

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Brand Focus · Unraid

Unraid RAID-Z2 vs RAID-Z1 Calculator

Compare usable TB, parity, and failure tolerance between RAID-Z2 and RAID-Z1 for Unraid NAS users.

Comparison Notes

This page compares RAID-Z2 and RAID-Z1 on identical hardware assumptions to help homelab builders choose between capacity efficiency and fault tolerance.

  • Disk size baseline: 8TB drives
  • Reserve policy: 10% filesystem headroom
  • Use the interactive tool for exact real-world constraints
Open Interactive Planner

Storage Capacity Table

Drives RAID-Z2 RAID-Z1 Delta
4x 8TB 14.40 TB 21.60 TB -7.20 TB
6x 8TB 28.80 TB 36.00 TB -7.20 TB
8x 8TB 43.20 TB 50.40 TB -7.20 TB
10x 8TB 57.60 TB 64.80 TB -7.20 TB
12x 8TB 72.00 TB 79.20 TB -7.20 TB

Unraid Planning Notes

Unraid users often optimize for incremental growth and flexible disk replacement, where parity planning and usable capacity targets evolve over time rather than all at once.

Brand / Region Glossary

Parity Disk

Dedicated parity disk(s) protecting data disks in the Unraid array model.

Cache Pool

Fast SSD/NVMe pool used for writes and application workloads.

Mover

Scheduled process that migrates data between cache and array tiers.

NAS Cluster Guides

Related Long-Tail Calculators

Sequential Long-Tail Navigation

FAQ

How should I select between RAID-Z2 and RAID-Z1?

Choose based on your risk tolerance, rebuild window, and performance profile. Higher parity usually lowers capacity but improves resilience.

Does this comparison include filesystem reserve?

Yes. The comparison table applies a 10% reserve baseline to reflect realistic operating headroom in NAS and homelab environments.

Which option is usually better for long-term homelab growth?

The better option is the one that keeps acceptable usable capacity while preserving safety margins during future disk expansions.

Which has more effective capacity: RAID-Z2 or RAID-Z1?

For Unraid users, this NAS planning scenario compares both modes at fixed drive sizes so you can see usable capacity differences before buying disks.