1. What is System Availability?

System availability is a metric that measures the proportion of time a system is operational and available for use. It's calculated using Mean Time Between Failures (MTBF) and Mean Time To Repair (MTTR).

2. How Does the Calculator Work?

The calculator uses the availability formula:

Where:

• \( MTBF \) — Mean Time Between Failures (hours)
• \( MTTR \) — Mean Time To Repair (hours)

Explanation: The formula represents the ratio of uptime to total time (uptime + downtime).

3. Importance of Availability Calculation

Details: Availability is a critical metric for system reliability assessment, service level agreements (SLAs), and infrastructure planning.

4. Using the Calculator

Tips: Enter MTBF and MTTR in hours. Both values must be positive numbers (MTBF > 0, MTTR ≥ 0).

5. Frequently Asked Questions (FAQ)

Q1: What is considered good availability?
A: "Five nines" (99.999%) is often the gold standard for critical systems, but requirements vary by application.

Q2: How is availability different from reliability?
A: Reliability measures failure frequency, while availability measures the proportion of time the system is operational.

Q3: Can availability exceed 1 (100%)?
A: No, availability is always between 0 (never available) and 1 (always available).

Q4: What affects system availability?
A: Factors include hardware quality, maintenance procedures, redundancy, and repair efficiency.

Q5: How can I improve availability?
A: Increase MTBF (better components/redundancy) or decrease MTTR (faster repair processes).