Azure's global infrastructure is one of the largest in the world, with data centres in over 60 regions across 140 countries. Understanding how it's organised is essential for designing resilient architectures and answering AZ-900 exam questions on availability and compliance.
Geographies
An Azure geography is a market (typically a country or group of countries) that contains one or more Azure regions. Geographies ensure that data residency and compliance requirements are respected — data stored in a geography stays within that geography by default.
Examples: United States, United Kingdom, European Union, Australia, Japan.
Regions
A region is a set of data centres in a defined geographic area, connected by a low-latency network. Azure has 60+ regions. Examples: East US, West Europe, Southeast Asia.
Why regions matter:
- Latency: Deploy close to your users.
- Data residency: Keep data within a country or regulatory boundary.
- Service availability: Not all Azure services are available in every region.
- Cost: Prices vary by region.
Region Pairs
Most Azure regions are paired with another region in the same geography. Region pairs:
- Are at least 300 miles apart to reduce the chance of both being affected by the same disaster
- Enable geo-redundant storage replication and geo-redundant database backups
- Receive Azure platform updates in a staggered rollout (reducing simultaneous outage risk)
- Example pairs: East US ↔ West US; North Europe ↔ West Europe; UK South ↔ UK West
Availability Zones
Availability Zones (AZs) are physically separate data centre facilities within a single region. Each zone has independent power, cooling, and networking. Zones are connected by high-bandwidth, ultra-low-latency fibre.
Using multiple AZs protects against:
- Power failures at a single facility
- Network outages within a zone
- Physical disasters affecting one zone
Not all Azure regions have Availability Zones. Check the Azure documentation for zone-enabled regions.
Infrastructure Comparison
| Concept | Azure | AWS | GCP |
|---|---|---|---|
| Geographic boundary | Geography | — | — |
| Geographic area | Region | Region | Region |
| Isolated data centre | Availability Zone | Availability Zone | Zone |
| Cross-region pairing | Region Pair | — | Dual-region |
Azure Edge Locations
In addition to regions and zones, Azure has:
- Azure CDN PoPs: 100+ edge nodes globally for content caching and acceleration
- Azure Front Door: Global load balancer and WAF with anycast edge presence
- Azure Edge Zones: Extensions of Azure regions into metropolitan areas for ultra-low-latency workloads (e.g., 5G applications)