- AWS has regions all around the world. A region is a cluster of Availability Zones (AZs).
- Each region has multiple AZs, ranging from a minimum of 2 to a maximum of 6 e.g.
us-east-1a, us-east-1b, ap-southeast-2a and so on.
- Each AZ is one or more data center with redundant power, networking and connectivity.
- Each AZ is geographically separated for disaster recovery but they are still connected with ultra-low latency networks.
- AZs are connected with high speed private link.
- Each AZ runs on its own physically distinct, independent infrastructure and is engineered to be highly reliable.
- Common points of failure like generators and cooling equipments are not shared across AZs.
- Most AWS services are region-scoped i.e. you provision and pay for services by region.
- Very few services are inherently multi-region e.g. Aurora Global, DynamoDB Global