What exactly are Windows Azure Instances? [closed]

Question

On Windows Azure Portal ( as of Jan 2013) What do i get when i scale the Windows Azure Website instance from 1 to 6? Does it mean there will be 6 physical instances of my website on the same server? In IIS terms are there 6 running websites all automatically load balanced?

But judging from the help text it refers to instances as processes? If so, my website will get 6 CPUs, RAM or what?

Cheers

Answer 1

Windows Azure Websites, unlike Windows Azure Web Roles, is a 'high-density' multi-tenancy platform which does not use virtual machines as a scale unit but processes.

When you use Web Roles (or Worker Roles, or Virtual Machines for that matter) every instance equals a virtual machine whose 'specs' are determined by the instance size selected.

When you use WebSites you can chose between a shared instance and a reserved instance:

Reserved instances are pretty much like web roles from a scale point of view so the scale unit is of a virtual machine (and you pay accordingly)

Shared instances use the high-density model in which multiple tenant may exist on the same virtual machine but each has it's own process with isolation being provided by the platform through sandboxing.

In the shared instance case the scale unit is not an entire machine but rather an additional process, which is very likely to run on a separate virtual machine.