A SAN file system (that is, a storage area network file system) is programming that enables the sharing of the same copies of files stored on common storage media among multiple servers that may have different operating systems. Without a SAN file system, although different servers may share common storage media (using virtualization approaches), they cannot share the same files. A SAN file system simplifies and streamlines SAN management, minimizes storage and retrieval time, optimizes the use of storage resources, allows network components to be scaled individually, and eliminates the need for storage redundancy.
The SAN programming consists of a client on each server that is written especially for the operating platform used by that server. To create or write to a file, the client makes a request to a common metadata server which controls traffic in the SAN. Once access is granted, a server can access the file without having to go through the metadata server, ensuring that most I/O will not be degraded in performance.