04-23-2020 07:26 PM
04-23-2020 07:26 PM
I would like to know how are VM are replicated in an availability zone. For example if I create one VM and choose the option of availability zone in two different zones, In each zone, will there be only one machine setup on a server or will it be setup in an availability set? What my understanding is that if I choose two availability sets, the machine will be running on two separate racks with their own FD and UD. If my machine is in two different zones, it will be only one instance of each machine running on one server in each zone. If those particular fault domain on which my machine is running, go down at the same time, I will loose my machine. If this is the case, shouldn't there be an option of creating an availability set first and then deploy them in different availability zones?
04-24-2020 09:08 AMSolution
When you deploy a VM in an Availability Zone, you are deploying it to a single AZ. When you chose 1, 2 or 3, you are just picking one of the AZs in the specified region. Each region has normally AZ 1, AZ 2 and AZ 3. If you want high-availability, you need to deploy more than one VM, in multiple AZs. For example, deploy VM1 in AZ 1 and VM2 in AZ 2. Each AZ corresponds to a distinct UD/FD.
Availability Sets are used when you want regional high availability (instead of zonal). In this case, when adding multiple VMs in an Availability Set, they will end up in different UDs and FDs.
See more details here.
04-24-2020 09:46 PM
Thanks for your reply. My understanding was that Azure would automatically create two VM's if you wanted them to be deploy in two zones or a set. Now that you explained it, choosing 1, 2 or 3 availability zones simply means that my VM will only be in one specified zone I choose. As a beginner, now it makes sense to me that you will always have to create multiple VM's if you want them paired in an availability set or an availability zone. If you create one VM and you want them in a single availability set, you have to create to VM's.@hspinto