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RAID Capacity Calculator Calculator

Resolve redundant array storage architectures instantly. Precise engine for calculating usable vs overhead space across RAID 0, 1, 5, 6, and 10.

Problem Parameters
Total Raw Capacity: 16 TB
Usable Capacity: 12 TB
Protection / Parity Space: 4 TB
Fault Tolerance: 1 Drive failure
Solution
Usable Capacity
16 TB
75%
Storage Efficiency
Fast
Read Speed
Comprehensive Guide

RAID Arrays: Redundant Enterprise Storage

Learn the principles of parity, striping, and fault tolerance equations used in Network Attached Storage (NAS) fleets.

What is RAID array computation?

RAID (Redundant Array of Independent Disks) is a data storage virtualization technology that combines multiple physical disk drive components into one or more logical units. Based on the selected RAID "level", administrators dictate how data is distributed across these disks—striking different balances between performance, reliability, and sheer storage volume. This Storage Converter allows you to predict your net usable capacity instantly prior to investing in new NAS drives.

The RAID 5 Equation

$\text{Usable} = (N - 1) \times \text{Capacity}$

Where N is the total number of drives. Because 1 drive's worth of space is distributed as parity across all drives, you lose strictly one drive's capacity.

Key Technical Applications

  • NAS Provisioning: Architecting Synology, QNAP, or TrueNAS servers with exact physical drive geometries for your client data.
  • Database Server Redundancy: Selecting RAID 10 for massive IOPS (Input/Output Operations Per Second) on high-transaction SQL databases.
  • Media Archival: Using RAID 6 (dual parity) for massive video storage arrays where total data loss during a multi-drive failure rebuild is unacceptable.

Visualizing the RAID Layouts

Our algorithm executes the standard enterprise definitions:

  • RAID 0: $N \times S$. Uses 100% capacity for speed via striping. 0 fault tolerance. If one drive dies, all data is mathematically wiped.
  • RAID 1: $(N / 2) \times S$. Uses 50% capacity by mirroring data exactly from Drive A to Drive B. Outstanding read speeds, half capacity.
  • RAID 5: $(N - 1) \times S$. Uses rotating parity. Needs $\ge 3$ drives. Very common.
  • RAID 6: $(N - 2) \times S$. Uses double parity. Needs $\ge 4$ drives. Can survive 2 simultaneous drive failures.
  • RAID 10: $(N / 2) \times S$. A stripe of mirrors. Needs $\ge 4$ drives (even numbers only). Incredible high availability and write performance.

By utilizing this Precision RAID Calculator, you ensure that your deployment fault tolerances are 100% architecturally sound. If you are comparing raw GB values against Windows GiB values, use our dedicated Storage Converter or estimate how long the RAID rebuild will take using Data Transfer Tool.

Frequently Asked Questions

Is RAID a backup?

Absolutely not. RAID provides hardware high-availability and fault tolerance (preventing downtime if a motor fails). It does NOT protect against accidentally deleting files, ransomware, fire, or theft.