Storage Capacity for RAID

Estimate usual RAID usable capacity when disks get equal size.

Your numbers

Usable capacity before overhead

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Before filesystem, controller metadata, spare disks and reserved space. RAID no be backup.

Formula

With N disks wey get the same size of S TB, usable capacity na NS for RAID0, S for RAID1, (N−1)S for RAID5, (N−2)S for RAID6, and NS/2 for RAID10. Redundancy no replace backup.

Estimate usual RAID usable capacity when disks get equal size.

Example wey show the calculation

Number of disks: 4
Capacity of smallest disk (TB, decimal): 4
Level of RAID: RAID 5

Usable capacity before overhead: 12 TB
Raw capacity before overhead: 16 TB

Where e fit work and limits

Before filesystem, controller metadata, spare disks and reserved space. RAID no be backup.

We check inputs for missing values and allowed ranges. Result wey pass the finite numeric range no go show. Rounding affect wetin display, while calculation use the model numeric precision.

Check your units and assumptions before you rely on result. Changing label no convert currency or physical unit.

Version of di formula: b2581d8d1987 · Example don get check: 2026-10-30

Method