Azure physical infrastructure

Physical Infrastructure Overview

• Datacenters: Facilities with resources arranged in racks, with dedicated power, cooling, and networking.
• Global Presence: Azure has datacenters worldwide, grouped into Azure Regions or Availability Zones.

Regions

• Definition: Geographical areas containing multiple networked datacenters.
• Purpose: To balance workloads and provide resource availability.
• Selection: When deploying resources, you select a region. Some services/features are region-specific.

Availability Zones

• Definition: Physically separate datacenters within a region, with independent power, cooling, and networking.
• Isolation: Designed to ensure that if one zone fails, others remain operational.
• Use Cases: For high availability and redundancy of critical applications and services.
• Types:
  • Zonal Services: Resources pinned to a specific zone (e.g., VMs, managed disks).
  • Zone-Redundant Services: Automatically replicated across zones (e.g., zone-redundant storage, SQL Database).
  • Non-Regional Services: Resilient to both zone-wide and region-wide outages.

Region Pairs

• Definition: Most regions are paired with another within the same geography, about 300 miles apart.
• Benefits: Replication across pairs for disaster recovery and minimizing downtime.
• Examples: West US paired with East US, South-East Asia paired with East Asia.
• Advantages:
  • Prioritized restoration of one region in each pair during outages.
  • Sequential rollout of updates to paired regions.
  • Data remains within the same geography for legal purposes.
• One-Direction Pairing: Some regions are paired in only one direction (e.g., West India and South India, Brazil South and South Central US).

Sovereign Regions

• Purpose: Isolated instances of Azure for compliance or legal reasons.
• Examples:
  • US Government: US DoD Central, US Gov Virginia, US Gov Iowa.
  • China: China East, China North (operated through a partnership with 21Vianet).