RAID 5 Disk Calculator

RAID 5 Capacity Formula:

\[ \text{Capacity} = (N - 1) \times \text{MinDriveSize} \]

RAID 5 Capacity (TB):

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1. What is a RAID 5 Disk Calculator?

Definition: This calculator estimates the usable storage capacity of a RAID 5 array based on the number of disks and their size.

Purpose: It helps IT professionals and system administrators plan storage arrays with optimal capacity and redundancy.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ \text{Capacity} = (N - 1) \times \text{MinDriveSize} \]

Where:

\( \text{Capacity} \) — Usable storage capacity (TB)
\( N \) — Number of disks in the array
\( \text{MinDriveSize} \) — Size of the smallest disk (TB)

Explanation: RAID 5 uses one disk's worth of space for parity data, so the usable capacity is (number of disks - 1) multiplied by the smallest disk size.

3. Importance of RAID 5 Capacity Calculation

Details: Proper capacity planning ensures you allocate sufficient storage for your needs while maintaining fault tolerance through parity.

4. Using the Calculator

Tips: Enter the number of disks (minimum 3) and the size of the smallest disk in TB. All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: Why does RAID 5 need at least 3 disks?
A: RAID 5 requires a minimum of 3 disks to provide both storage capacity and parity protection.

Q2: What happens if disks are different sizes?
A: The array will use the smallest disk size for all disks, so it's best to use identical drives.

Q3: How does this differ from RAID 6 calculation?
A: RAID 6 uses two disks for parity, so its capacity would be (N - 2) × MinDriveSize.

Q4: What about overhead from filesystems?
A: This calculates raw capacity. Actual usable space will be slightly less due to filesystem overhead.

Q5: Can I mix drive types (HDD/SSD)?
A: While technically possible, it's not recommended as it can impact performance and reliability.