Availability of resources

Not all resources are available in every Azure region. If application architecture demands a resource and it is not available in a region, choosing that region will not help. Instead, a region should be chosen based on the availability of all resources required by the application. It might be so that the resource might not be available while developing the application architecture and could be on the Azure roadmap to make it available subsequently.

For example, log analytics is not available in all regions. Data transfer to log analytics would incur egress network cost if the application is deployed in a region that does not have log analytics (previously known as operational management suite). Similarly, Azure key vault provides services to only resources that are co-located in the same region. Another example is that an Azure virtual network can host virtual machines, load balancers from same regions. Virtual machines from different regions cannot be part of the same virtual network.