RAID Calculator

Category: Technology
- March 31, 2025
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Calculate storage capacity, performance metrics, and fault tolerance for different RAID configurations. This calculator helps you plan your storage array based on your requirements for capacity, redundancy, and performance.

Storage Configuration

RAID Configuration
Drive Configuration
Drive Performance (Optional)
MB/s
MB/s
ms

Advanced Options

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About RAID Technology

RAID (Redundant Array of Independent Disks) combines multiple physical disk drives into one or more logical units for data redundancy, performance improvement, or both. Different RAID levels offer different balances between key objectives: reliability, availability, performance, and capacity.

Common RAID Levels
  • RAID 0 (Striping): Data is split across all drives. Offers best performance but no redundancy. If one drive fails, all data is lost.
  • RAID 1 (Mirroring): Data is duplicated on two or more drives. Provides excellent redundancy but reduces capacity by 50%.
  • RAID 5 (Striping with Parity): Data is striped across drives with distributed parity. Can survive one drive failure.
  • RAID 6 (Striping with Double Parity): Similar to RAID 5 but with dual parity. Can survive two simultaneous drive failures.
  • RAID 10 (1+0): Combines mirroring and striping. Offers good performance and redundancy but requires at least 4 drives.
Key Considerations
  • Capacity: Different RAID levels use different amounts of space for redundancy.
  • Performance: Read and write speeds can vary significantly between RAID levels.
  • Fault Tolerance: How many drives can fail without data loss varies by RAID level.
  • Rebuild Time: Larger drives take longer to rebuild after a failure, increasing vulnerability.
  • RAID is Not Backup: RAID protects against drive failure, not user error, corruption, or disasters.
Best Practices
  • Use identical drives (same size, speed, and ideally same model) for best performance and reliability.
  • Implement a proper backup strategy in addition to RAID.
  • Consider using a hardware RAID controller for critical systems instead of software RAID.
  • Monitor drive health and have spare drives ready for quick replacement.
  • For maximum data safety, follow the 3-2-1 backup rule: 3 copies, 2 different media types, 1 off-site.

What Is the RAID Calculator?

The RAID Calculator is a practical tool that helps you estimate the storage capacity, performance, and fault tolerance of various RAID (Redundant Array of Independent Disks) setups. It is built to support anyone planning or managing data storage—whether you're a home user with multiple hard drives or a system administrator overseeing large arrays.

By adjusting simple inputs like the number of drives, individual drive size, and the RAID level, you can instantly see how much usable space you'll have, how fast your storage system can perform, and how resilient it is to drive failures.

Key Features

  • Supports popular RAID levels including RAID 0, 1, 5, 6, 10, and JBOD
  • Calculates usable capacity, total read/write speed, IOPS, and fault tolerance
  • Optional inputs for file system overhead and drive performance metrics
  • Visual breakdown of space efficiency, parity drives, and lost capacity
  • Clear guidance on RAID suitability for different use cases

Formula Used for Storage Calculation

The calculator uses different formulas depending on the selected RAID level. Here's a general format:

Usable Storage = (N × D) - P
Where:
N = Number of drives
D = Capacity per drive
P = Space used for redundancy or parity

Each RAID type changes how P is calculated. For example, RAID 5 subtracts one drive's worth of space for parity, while RAID 6 subtracts two.

How to Use the Calculator

Using the RAID Calculator is straightforward and requires just a few steps:

  • Select a RAID Level: Choose the RAID type that fits your needs for speed, redundancy, or capacity.
  • Set Number of Drives: Pick how many drives are in your array. The tool ensures you meet minimum drive requirements per RAID type.
  • Enter Drive Capacity: Specify how large each drive is. You can use either GB or TB as units.
  • (Optional) Add Performance Details: Input drive read/write speeds and IOPS to get performance estimates.
  • Adjust Advanced Settings: Tweak file system overhead or toggle detailed breakdowns.
  • Click "Calculate RAID Configuration": Your storage summary and performance metrics will appear instantly.

Why This Tool Is Useful

This calculator simplifies RAID planning. It helps you answer important questions like:

  • How much usable space will I actually get?
  • What happens if a drive fails?
  • Is this configuration fast enough for my workload?
  • How much space is lost to redundancy or overhead?

Whether you're configuring a NAS for backups, setting up a high-speed video editing rig, or maintaining enterprise data storage, the RAID Calculator gives you quick, accurate insights to make informed decisions.

Frequently Asked Questions (FAQ)

What is RAID?

RAID stands for Redundant Array of Independent Disks. It combines multiple physical drives into a single storage unit to improve speed, reliability, or both.

Which RAID level should I choose?

It depends on your priorities:

  • RAID 0: Best for speed, no fault tolerance
  • RAID 1: Full redundancy, lower capacity
  • RAID 5: Balance of capacity, performance, and redundancy
  • RAID 6: Better protection for larger arrays
  • RAID 10: Excellent performance and redundancy, lower usable space
  • JBOD: Combines drives without redundancy or speed gains

Is RAID a backup?

No. RAID protects against drive failure, but it won’t protect against file deletion, corruption, or ransomware. You still need a proper backup system.

Does the calculator include file system overhead?

Yes. You can manually set a percentage to account for file system overhead, which slightly reduces actual usable storage.

Why are read and write speeds different?

RAID configurations distribute data differently. Some levels are faster for reads (like RAID 0), while others slow down writes due to parity calculations (like RAID 5/6).

Related Concepts You May Want to Know

  • IOPS: Measures how many read/write operations your array can perform per second.
  • Throughput: The speed at which data is read or written (MB/s or GB/s).
  • Parity: Redundant data that allows RAID arrays to recover from drive failures.
  • Drive Rebuild: The process of restoring data after replacing a failed drive.

This RAID Calculator helps you plan smarter by giving clear insight into how RAID affects your storage setup—without requiring deep technical knowledge. It's a must-have tool for anyone working with multiple drives and serious about protecting their data.