1. What is RAID 5 Storage Efficiency?

Definition: RAID 5 storage efficiency measures the usable storage percentage in a RAID 5 array, accounting for parity overhead.

Purpose: Helps IT professionals determine how much of their total drive capacity will be available for data storage in a RAID 5 configuration.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• Efficiency — Ratio of usable space to total space (decimal)
• N — Number of drives in the array (minimum 3)

Explanation: In RAID 5, one drive's worth of capacity is used for parity data, so usable space is (N-1) drives' worth.

3. Importance of RAID 5 Efficiency Calculation

Details: Understanding storage efficiency helps in capacity planning, cost estimation, and comparing different RAID levels.

4. Using the Calculator

Tips: Enter the number of drives in your RAID 5 array (minimum 3). The calculator will show the efficiency as both a decimal and percentage.

5. Frequently Asked Questions (FAQ)

Q1: Why is the minimum number of drives 3?
A: RAID 5 requires at least 3 drives - 2 for data striping and 1 for parity.

Q2: How does drive size affect this calculation?
A: The efficiency percentage remains the same regardless of individual drive sizes, but larger drives mean more absolute capacity.

Q3: What's the maximum efficiency possible with RAID 5?
A: Efficiency approaches 100% as you add more drives (e.g., 96.7% with 30 drives), but never reaches 100%.

Q4: How does this compare to RAID 0 or RAID 1?
A: RAID 0 has 100% efficiency (no redundancy), RAID 1 has 50% efficiency (mirrored drives).

Q5: Does this account for filesystem overhead?
A: No, this is purely the RAID efficiency. Filesystems will have additional small overhead.