Understand Azure Availability Sets and Zones to design resilient, highly available workloads and cloud architectures
Complete Guide Availability Sets Availability Zones AZ-104 Azure Availability Set vs Availability Zone: What's the Difference? Both promise the same thing — keep your application running when something underneath it fails. But "something" means very different things at each scale. An availability set protects you from a rack losing power. An availability zone protects you from the entire datacenter that rack sits in going dark. Confusing the two, or assuming one subsumes the other, is how "highly available" architectures turn out not to be. 99.95% SLA with 2+ VMs in an Availability Set — about 4.4 hours of downtime/year 99.99% SLA with VMs spread across 2+ Availability Zones — about 52 minutes of downtime/year Rack vs Datacenter An Availability Set protects against a rack failing. An Availability Zone protects against the datacenter failing 3 + 20 Max fault domains (3) and update domains (20) in an Availability Set — fixed at creation, never changeable after Tab...