Regions and Availability Zones
The most important AWS concept to get right early.
AWS Regions & Availability Zones
AWS Global
30+ regions worldwide
Region (us-east-1)
closest to your users
AZ-1a
data center A
AZ-1b
data center B
AZ-1c
data center C
Your App
primary
Your App
failover copy
A Region is a geographic area where AWS runs a cluster of data centers, like us-east-1 (Virginia) or ap-south-1 (Mumbai). AWS operates 30+ regions worldwide.
An Availability Zone (AZ) is a physically separate data center inside a Region, with its own independent power, cooling, and networking.
The rule that matters: always deploy production workloads across at least 2 Availability Zones. If one AZ fails entirely, your application stays running on the other.
A Region is a geographic area. An Availability Zone is one physically independent data center inside it. Spread production traffic across multiple AZs so a single data center failure doesn't take your app down with it.