NAS & RAID Calculator

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8x 16TB RAID-Z1 NAS Calculator | Usable TB

Estimate usable TB, parity overhead, and fault tolerance for 8x 16TB in RAID-Z1. Includes reserve planning for NAS and homelab arrays.

Capacity Snapshot

Raw Capacity

128.00 TB

Usable Capacity

100.80 TB

Fault Tolerance

1 drive

Efficiency

87.5%

ZFS single-parity equivalent of RAID 5; common for smaller homelab pools. This scenario applies a 10% filesystem reserve.

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Alternative Mode Comparison

Mode Usable Tolerance Efficiency
RAID 5 100.80 TB 1 drive 87.5%
RAID 6 86.40 TB 2 drives 75.0%
RAID 10 57.60 TB 1 drive per mirror pair* 50.0%
RAID-Z1 100.80 TB 1 drive 87.5%
RAID-Z2 86.40 TB 2 drives 75.0%

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FAQ

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.

Should I optimize this 8-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 much effective storage does 8x 16TB RAID-Z1 provide?

This NAS planning scenario estimates 100.80 TB usable after a 10% reserve from 128.00 TB raw.

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.