The SAN File System client code that is installed on a UNIX-based client is called a Virtual File System (VFS). The VFS is a subsystem of an UNIX-based client's virtual file system layer. It directs all metadata operations to a metadata server and all data operations to storage devices that are attached to your SAN. The VFS makes the metadata that is visible to the client's operating system, as well as any applications that run on the client, look identical to metadata read from a native, locally-attached file system.
root@aix2:/# df Filesystem 1024-blocks Free %Used Iused %Iused Mounted on /dev 32768 23024 30% 1413 9% / /dev/hd1 950272 8096 100% 29103 13% /usr SANFS 16728064 16154624 4% 1 1% /sanfs
UNIX-based clients use standard UNIX permission semantics (such as read, write, and execute bits, and owner and group IDs) that make the global namespace appear as if it is a local UNIX file system.