The global namespace is the key to SAN File System. It gives all SAN File System clients common access to all files and directories, and ensures that all SAN File System clients have consistent access and a consistent view of the data and files managed by SAN File System. Having common access to all files reduces the need to store and manage duplicate copies of data and simplifies the backup process. Security mechanisms, such as permissions and access control lists (ACLs), restrict the visibility of files and directories.