Availability Sets

• Way to ensure your application remains online if a high-impact maintenance event is required, or if a hardware failure occurs.

• Made up of Update domains (UD) and Fault domains (FD).

• Update domains - The update is sequenced through update domains. Sequencing updates using update domains ensures that the entire datacentre isn't unavailable during platform updates and patching.

• Fault domains - A server rack = Set of hardware components that share a single point of failure. To be fault tolerant to a certain level, you need multiple fault domains at that level.

• VMs in an availability set = VMs split up in different fault domains/server racks

• Create different availability sets for different workloads.