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Synology RAID 6 vs RAID 5 Storage Calculator

Compare usable capacity, fault tolerance, and efficiency between RAID 6 and RAID 5 for Synology 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

Synology Planning Notes

Synology users usually optimize for predictable rebuild behavior and conservative free-space policies, especially when using large-capacity SHR/RAID pools for media and backup workloads.

Brand / Region Glossary

SHR

Synology Hybrid RAID that improves flexibility when mixing drive sizes.

Btrfs Snapshots

Point-in-time snapshots used for rollback and data protection policies.

Storage Pool

Logical disk group where RAID layout is created before volumes are provisioned.

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

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.

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.

How should I choose 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.

Can two layouts with similar available space still have very different rebuild risk?

Yes. Similar usable TB does not imply similar failure tolerance or rebuild exposure. Capacity and resiliency should be evaluated together.