The Windows Azure Fabric Controller deploys an instance of a Windows Azure role onto a virtual machine (VM) as three virtual hard disks (VHD). The Guest OS image is deployed to the D: drive; the role image is deployed to the E: or F: drive; while the C: drive contains the service configuration and the local storage available to the instance. Only code running with elevated privileges can write anywhere other than local storage.
Each instance has read-write access to a reserved space on the C: drive. The amount of space available depends on the instance size, and ranges from 20 GB for an extra small instance to 2,040 GB for an extra large instance. This storage space is reserved by being specified in the service definition file, ServiceDefinition.csdef, for the service. Note that RoleEnvironment.GetLocalResource() should be invoked to retrieve the actual path to local storage.
The LocalStorage element for a role in the service definition file requires a name...