1. What is AWS Availability?

AWS availability refers to the percentage of time a service is operational and accessible to users. It's typically expressed as a decimal or percentage (e.g., 0.999 or 99.9%).

2. How Does the Calculator Work?

The calculator uses the simple formula:

Where:

• Downtime Fraction — The fraction of time the service is unavailable (0 to 1)

Explanation: This calculation provides the basic availability metric, which can be extended to calculate annual downtime minutes or other SLA metrics.

3. Importance of Availability Calculation

Details: Availability is a key SLA metric for cloud services. AWS typically offers different availability levels (e.g., 99.9%, 99.95%, 99.99%) with corresponding pricing tiers.

4. Using the Calculator

Tips: Enter the downtime fraction as a decimal between 0 and 1 (e.g., 0.001 for 0.1% downtime). The calculator will compute the corresponding availability.

5. Frequently Asked Questions (FAQ)

Q1: What's considered good availability for AWS services?
A: Standard AWS services typically offer 99.9% (three nines) availability, while higher-tier services may offer 99.95% or 99.99%.

Q2: How does this relate to "nines" of availability?
A: Each "nine" represents an order of magnitude improvement. 99.9% is three nines, 99.99% is four nines, etc.

Q3: What's the difference between availability and uptime?
A: Availability considers both planned and unplanned downtime, while uptime typically only considers unplanned outages.

Q4: How can I improve my AWS availability?
A: Use multi-AZ deployments, implement auto-scaling, and design for fault tolerance following AWS best practices.

Q5: Does this calculator account for regional outages?
A: This is a basic calculator. For comprehensive SLA calculations, consider region-specific availability and redundancy.