Availability sets are a basic way to let Microsoft Azure know that these two VMs belong to a cluster or application group and are now allowed to go down together. For VMs within a availability Azure manages that these machines run within different fault and update domains of an Azure region:
- Update domain: Update domain in Azure means that all physical servers in an update domain will get host updates such as firmware, drivers, and OS updates at the same time.
- Fault domain: Fault domain in Azure means that all servers in these domains run in the same fire sections, with the same air conditions or electrical source. This means all physical servers within those domains can have an outage at the same time.
The following diagram is a schematic view of the distribution of a VM within an availability set:
With Azure VM managed disks, there is an additional option that comes with availability sets. Azure also takes care that managed disks for VMs within an availability...