1. What is System Availability?

System Availability is a metric that measures the proportion of time a system is in a functioning condition. 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 equation represents the ratio of uptime to total time (uptime + downtime).

3. Importance of Availability Calculation

Details: System availability is crucial for assessing reliability, planning maintenance, and ensuring service level agreements (SLAs) are met.

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 industry.

Q2: How is MTBF different from MTTF?
A: MTBF (repairable systems) includes repair time, while MTTF (non-repairable) is time until final failure.

Q3: Can availability exceed 100%?
A: No, maximum theoretical availability is 100% (perfect system with no downtime).

Q4: How does this relate to reliability?
A: Availability considers both reliability (MTBF) and maintainability (MTTR).

Q5: What affects system availability?
A: Component reliability, redundancy, maintenance processes, and environmental factors.