What is Availability Set and Availability Zone in Azure? In Availability Set, VM`s copy is created and is isolated with separate physical servers, computer racks, storage units, network switches in a data center within a region so if one of the VM stops working then still we have the copy of the VM working within the same datacenter. While Availability Zone ensures that complete datacenter data is replicated to another place at a distance within the same region so that even if complete data center fails due to any reason then also Availability of data is ensured.