In enterprise storage, a SAN file system is a file system which has been optimized to be shared by multiple clustered servers over a storage area network. SAN file systems are like network attached storage (NAS) protocols (like SMB and NFS) in that they allow multiple computers to access the same file system (and even file) at the same time. However, unlike NAS networks, SAN file systems use a faster block storage access method.

There are different architectural approaches to a SAN File System. Some distribute file information across all the servers in a clusters (fully distributed). Others utilize a centralized metadata server (centralized). Both achieve the same result of enabling all servers to access all the data on a SAN.