1. What is a RAID Capacity Calculator?

Definition: This calculator estimates the usable storage capacity in a RAID array based on the number of drives, parity drives, and individual drive size.

Purpose: It helps IT professionals and system administrators determine the effective storage capacity when planning RAID configurations.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

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

Explanation: The total number of drives minus parity drives gives the number of data drives, multiplied by drive size gives usable capacity.

3. Importance of RAID Capacity Calculation

Details: Proper capacity estimation ensures you allocate sufficient storage for your needs while maintaining the desired level of redundancy.

4. Using the Calculator

Tips: Enter the total number of drives (minimum 1), number of parity drives (default 1), and drive size in TB. Ensure N > P.

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between N and P?
A: N is total drives in the array, P is drives dedicated to parity/redundancy (not available for data storage).

Q2: What RAID levels does this calculator support?
A: It works for RAID 5 (P=1), RAID 6 (P=2), and similar parity-based RAID configurations.

Q3: How do I account for different drive sizes?
A: For mixed drives, use the smallest drive size in the array for accurate calculation.

Q4: Does this include formatting overhead?
A: No, the result is raw capacity. Expect 5-10% less usable space due to filesystem overhead.

Q5: What's a typical parity configuration?
A: RAID 5 uses 1 parity drive, RAID 6 uses 2. Some advanced systems may use more.