NAS & RAID Calculator

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APAC 4x 8TB RAID 5 Calculator

Estimate usable capacity, fault tolerance, and efficiency for APAC homelab buyers using 4x 8TB in RAID 5.

Capacity Snapshot

Raw Capacity

32.00 TB

Usable Capacity

21.60 TB

Fault Tolerance

1 drive

Efficiency

75.0%

Balanced capacity and redundancy, but rebuild stress can be high on large disks. This scenario applies a 10% filesystem reserve.

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Alternative Mode Comparison

Mode Usable Tolerance Efficiency
RAID 5 21.60 TB 1 drive 75.0%
RAID 6 14.40 TB 2 drives 50.0%
RAID 10 14.40 TB 1 drive per mirror pair* 50.0%
RAID-Z1 21.60 TB 1 drive 75.0%
RAID-Z2 14.40 TB 2 drives 50.0%

APAC Buyer Context

APAC builders frequently compare availability windows and procurement variance, which makes robust fallback capacity and staged scaling useful in practice.

Brand / Region Glossary

Procurement Variance

Regional differences in disk availability and replacement lead times.

Spare Strategy

Policy of keeping spare disks available to reduce recovery delay risk.

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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.

Should I optimize this 4-drive plan for available space 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.

How many disk failures can RAID 5 tolerate in this setup?

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

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.