Regions, Availability Zones, and Latency

Regions are geographic choices

A region is a cluster of data centers in a geographic area, such as us-east-1, westeurope, or europe-west1. You pick a region when you create many resources. Data residency rules and user location often drive the choice.

Availability zones reduce blast radius

An availability zone (AZ) is an isolated location inside a region with independent power and networking. Spreading copies of an app across AZs helps survive a single facility failure. Not every service is multi-AZ by default—check the product docs.

Latency is distance plus hops

Every request travels over networks. Putting compute and data far from users adds delay. Putting a database in one region and an app in another can quietly hurt performance and raise transfer costs.

List regions from the CLI

Confirm which regions your account can use before you deploy.

# AWS
aws ec2 describe-regions --query 'Regions[].RegionName' --output text

# Azure
az account list-locations --query '[].name' --output tsv

# Google Cloud
gcloud compute regions list