Azure File Storage allows a storage account to be mounted as a shared drive across the Azure worker roles.
When configuring your Azure Storage account details during the configuration process in the administration tool, you can elect to share an area of storage and map a drive letter to it.
In the above example, a shared drive assigned to the drive letter M (1) will be created and mapped to the path \test (2).
The file storage drive acts as a local NTFS volume that is mounted on the server’s file system and that is accessible to code running in a role. The data written to the drive is persisted in the storage account. Because data written to the drive is stored in the storage account, the data is maintained even if the role instance is recycled. For this reason, File Storage can be used to run an application that needs to use information that will persist between recycles.
In the Enterprise Server for .NET context, a File Storage drive provides an alternative to deploying programs and data into SQL Azure database instances. The main benefit in using an Azure drive over a database deployment is speed.