1. What is System Availability?

System Availability is a measure of the percentage of time that a system is operational and available for use. It's calculated using the 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 shows the ratio of uptime to total time (uptime + downtime). Higher values indicate more reliable systems.

3. Importance of Availability Calculation

Details: Availability is crucial for system reliability assessment, maintenance planning, and service level agreements (SLAs). It helps organizations predict and improve system performance.

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 and application.

Q2: How does availability differ from reliability?
A: Reliability measures probability of failure-free operation, while availability measures the proportion of time a system is operational.

Q3: Can availability exceed 1?
A: No, availability is always between 0 (never available) and 1 (always available), often expressed as a percentage.

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

Q5: How can availability be improved?
A: By increasing MTBF (better components/redundancy) or decreasing MTTR (faster repairs/better maintenance).