Reliability Week: Regions & AZs

While Clouds are built in Data Centers - we don't use the term when we use Cloud to build our platforms.

Cloud uses the concept of 'availability zones' - a cluster of one or more datacenter facilities logically grouped together.

Each availability zone ('AZ') is isolated from the other in two ways.

• Physically isolated to minimise impact - due to say, a natural disaster like a tornado.
• Infrastructure - they have isolation of cooling, power, or other physical components to prevent failure.

Multiple availability zones are grouped together into a region. A region is a geographically scoped collection of availability zones - with isolation of control plane, and allows users to control data movement to be scoped to the region (and hence country) that it is deployed.

When starting or building on Cloud, the first question is whether to go single availability zone, multi availability zone, multi region, or even multi-Cloud. The second question is how.

We will expand on this more later in Reliability Week - join us in Day 10 to cover design patterns for multi-AZ and multi-region deployments.