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TrueNAS RAID 6 vs RAID 5 Storage Calculator

Compare usable capacity, fault tolerance, and efficiency between RAID 6 and RAID 5 for TrueNAS NAS users.

Comparison Notes

This page compares RAID 6 and RAID 5 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 6 RAID 5 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

TrueNAS / ZFS Planning Notes

TrueNAS and ZFS planners usually care about parity width, scrub cadence, and healthy operating headroom. Capacity is only one part of pool durability.

Brand / Region Glossary

vdev

A virtual device group in ZFS; multiple vdevs form a storage pool.

Scrub

Background integrity scan that verifies checksums and repairs parity mismatches.

RAID-Z Expansion

ZFS feature set and planning topic for growing parity groups safely.

Related Long-Tail Calculators

FAQ

Does RAID 6 rebuild faster than RAID 5?

Rebuild behavior depends on array width, disk size, and workload pressure. This page focuses on capacity and tolerance; benchmark your actual platform before final choice.

How should I select between RAID 6 and RAID 5?

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

Which has more usable storage headroom: RAID 6 or RAID 5?

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

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.