1. What is RAID 5 Capacity Calculator?

Definition: This calculator estimates the usable storage capacity in a RAID 5 array based on the number of drives and their individual sizes.

Purpose: It helps IT professionals and system administrators plan storage arrays by determining the available capacity after accounting for RAID 5 parity.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( \text{Capacity} \) — Usable storage capacity (TB)
• \( N \) — Number of drives in the array
• \( \text{DriveSize} \) — Size of each individual drive (TB)

Explanation: RAID 5 uses one drive's worth of space for parity information, so the total capacity is (number of drives - 1) multiplied by the drive size.

3. Importance of RAID 5 Capacity Calculation

Details: Proper capacity planning ensures you allocate sufficient storage for your needs while maintaining the fault tolerance benefits of RAID 5.

4. Using the Calculator

Tips: Enter the number of drives (minimum 3) and the size of each drive in TB. All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: Why does RAID 5 need at least 3 drives?
A: RAID 5 requires a minimum of 3 drives to provide both redundancy (through parity) and increased capacity.

Q2: What happens if a drive fails in RAID 5?
A: The array continues operating in degraded mode, and data can be rebuilt when the failed drive is replaced.

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

Q4: Does this account for filesystem overhead?
A: No, this is raw capacity. Actual usable space will be slightly less due to filesystem formatting.

Q5: Can I mix different drive sizes?
A: While possible, RAID 5 typically uses the smallest drive's size for all drives in the array.