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RAID capacity calculator

Usable space, fault tolerance and storage efficiency for RAID 0, 1, 5, 6 and 10.

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Usable capacity 24 TB

How it works

RAID 5: (n − 1) × size · RAID 6: (n − 2) × size

RAID 0 stripes data across all drives for speed but loses everything if one fails. RAID 1 mirrors: every drive holds the same data. RAID 5 spends one drive’s worth of space on parity and survives one failure; RAID 6 spends two and survives two. RAID 10 mirrors pairs and stripes across them. With mixed sizes, every drive counts as the smallest one. RAID isn’t a backup.

  1. Drives’ worth of data RAID 5 (single parity) → 3 × 8 TB
  2. Usable = data drives × size 3 × 8,000 GB = 24 TB

Good to know

  • RAID 5 needs at least 3 drives, RAID 6 and 10 at least 4 (RAID 10 an even number). Drive makers count 1 TB as 10¹² bytes; operating systems show TiB (2⁴⁰).

Printed from rocketcalc.io/computing/raid