What are cloud regions and availability zones

Short answer

Regions are geographic areas; availability zones (AZs) are isolated data centers within a region.

How it works

• A region is a broad geographic area (e.g., US-East, Europe-West).
• An AZ is one or more discrete data centers with independent power, cooling, and networking.
• Deploying across multiple AZs provides high availability.

Example

An application runs web servers in us-east-1a and us-east-1b with a database replicated across both. If one AZ fails, traffic fails over to the other.

Why it matters

Choosing the right region affects latency, data sovereignty, and pricing. Multi-AZ deployments protect against single-data-center failures.