Do multiple instances of a single Azure Web App share a single disk?

Question

I'm developing an app in in Azure Web Apps (formerly Websites) and want to be sure I understand how the local disk is used in a multiple instance scenario. When I scale to multiple instances, do they share a single virtual disk with all of the app files?

Consider this example:

• An app running on 5 instances
• A page in the app that uploads a file to the local disk, say to Server.MapPath("~/Content") (I know Storage would be better, but just for concept)
• Will all 5 instances have access to this file, or will it only exist on the instance where it was uploaded?

Answer 1

Yes, all your instances will be sharing the same persistent state, which includes everything under d:\home (your site bits are in d:\home\site\wwwroot).

There is also temp space under d:\local which is not shared, but this won't hurt your scenario.

See this for more detail on this topic.