The Foundation of Cloud Resilience
AWS operates a global infrastructure that spans the planet. Understanding this infrastructure is crucial for designing highly available, fault-tolerant applications. The three fundamental concepts you need to understand are Regions, Availability Zones, and Edge Locations.
Regions
An AWS Region is a physical location around the world where AWS clusters data centers. Each Region is completely independent and isolated from other Regions, which helps achieve the greatest possible fault tolerance and stability. When you view your resources, you'll only see the resources tied to the Region you've specified.
Choosing a Region
Consider four factors when choosing a Region: compliance requirements, proximity to customers, service availability, and pricing. Not all AWS services are available in all Regions, and prices vary by Region. Data sovereignty laws may require your data to stay in a specific geographic area.
Availability Zones
Each Region has multiple isolated locations known as Availability Zones (AZs). Each AZ is one or more discrete data centers with redundant power, networking, and connectivity. AZs within a Region are connected through low-latency links, allowing you to build highly available applications that automatically fail over between zones.
| Region | Code | AZs | Launch Year |
|---|---|---|---|
| US East (N. Virginia) | us-east-1 | 6 | 2006 |
| US West (Oregon) | us-west-2 | 4 | 2011 |
| EU (Ireland) | eu-west-1 | 3 | 2007 |
| Asia Pacific (Tokyo) | ap-northeast-1 | 4 | 2011 |
| Asia Pacific (Sydney) | ap-southeast-2 | 3 | 2012 |
Edge Locations
Edge Locations are endpoints for AWS services that are used for caching content. Amazon CloudFront uses edge locations to cache copies of your content closer to your customers for faster delivery. There are far more edge locations than Regions — over 400 points of presence in 90+ cities across 40+ countries.
- CloudFront: Content delivery network for static and dynamic content
- Route 53: DNS queries resolved at the edge for low latency
- AWS Global Accelerator: Optimize routing to your applications
- Lambda@Edge: Run code closer to your users
“Think globally, deploy regionally. Design your architecture to work across multiple availability zones by default. Only spread across regions when you have specific requirements for geographic distribution or disaster recovery.”