We have created Zone redundancy enabled App Service Plan and has couple of Web Apps under it. Instance count is 3. Now we wanted to validate if Zone1 gets down how Microsoft handles the resiliency. This test is required from our test team. If I shutdown App service, will my App service which gets replicated in zone2/zone3 will work.

CodePudding user response：

Unfortunately that can not be tested unless you can make the whole datacenter where 1 of the instances is running go down. The 3 instances that you currently have are spread across the 3 availability zones, if you shutdown one of the webappss it will just not be using any of the instances and any requests to it will be rejected. However if you have an app service running on 3 instances and the 3 of them are running in the same datacenter, once that datacenter goes down then you are completely down, while with zone redundancy if 1 datacenter goes down you still have other 2 instances running in two other datacenters.