Availability zone (AZ)

An availability zone (AZ) is an isolated cluster of one or more physically separate data centers within a single cloud region, each with its own power, cooling and network path, so a failure in one AZ doesn't take down the others. Hyperscalers typically deploy three or more AZs per region, spaced kilometers apart on independent utility feeds, so customers can replicate workloads across zones for high availability without the latency penalty of a multi-region deployment — inter-AZ round-trip latency within a region is usually under 2 milliseconds. AWS introduced the model in 2008; Azure, Google Cloud and Oracle Cloud have since built comparable AZ structures, and multi-AZ deployment is now the baseline enterprises expect from a cloud region. Microsoft's newest India cloud region, for example, launched across three availability zones in Hyderabad in August 2026.