Many legacy applications rely on file shares, a dependency that has complicated moving these applications to the cloud. File storage offers cloud-based file shares, so that you can migrate legacy applications to Azure quickly and without costly rewrites.
Applications running in Azure virtual machines or cloud services can mount a File storage share to access file data, just as a desktop application would mount a typical SMB share. Any number of application components can mount and access the File storage share simultaneously.
Since a File storage share is a standard SMB 2.1 file share, applications running in Azure can access data in the share via file sytem I/O APIs. Developers can therefore leverage their existing code and skills to migrate existing applications. IT Pros can use PowerShell cmdlets to create, mount, and manage File storage shares as part of the administration of Azure applications.
Like the other Azure storage services, File storage exposes a REST API for accessing data in a share. On-premise applications can call the File storage REST API to access data in a file share. This way, an enterprise can choose to migrate some legacy applications to Azure and continue running others from within their own organization. Note that mounting a file share is only possible for applications running in Azure; an on-premise application may only access the file share via the REST API.
Distributed applications can also use File storage to store and share useful application data and development and testing tools. For example, an application may store configuration files and diagnostic data such as logs, metrics, and crash dumps in a File storage share so that they are available to multiple virtual machines or roles. Developers and administrators can store utilities that they need to build or manage an application in a File storage share that is available to all components, rather than installing them on every virtual machine or role instance.File-Storage