nfs(7)							 Miscellaneous Information Manual						    nfs(7)

NAME

       nfs, NFS - network file system

DESCRIPTION

       The  Network File System (NFS) allows a client node to perform transparent file access over the network.  By using NFS, a client node oper-
       ates on files residing on a variety of servers and server architectures, and across a variety of operating systems.  File access  calls	on
       the  client  (such  as  read  requests)	are converted to NFS protocol requests and sent to the server system over the network.	The server
       receives the request, performs the actual file system operation, and sends a response back to the client.

       NFS operates in a stateless manner using remote procedure calls (RPC) built on top of an external data representation (XDR) protocol.   The
       RPC protocol enables version and authentication parameters to be exchanged for security over the network.

       A server grants access to a specific file system to clients by adding an entry for that file system to the server's file.

       A  client  gains access to that file system using the command to request a file handle for the file system (see mount(1M)).  (A file handle
       is the means by which NFS identifies remote files.)  Once a client mounts the file system, the server issues a file handle  to  the  client
       for  each  file	(or directory) the client accesses.  If the file is removed on the server side, the file handle becomes stale (dissociated
       with a known file), and the server returns an error with set to

       A server can also be a client with respect to file systems it has mounted over the network; however, its  clients  cannot  directly  access
       those  file systems.  If a client attempts to mount a file system for which the server is an NFS client, the server returns with set to The
       client must mount the file system directly from the server on which the file system resides.

       The user ID and group ID mappings must be the same between client and server.  However, the server maps UID 0 (the  superuser)  to  UID	-2
       before performing access checks for a client.  This process prevents gaining superuser privileges on remote file systems.

RETURN VALUE

       Generally,  physical  disk I/O errors detected at the server are returned to the client for action.  If the server is down or inaccessible,
       the client receives the message:

       where is the hostname of the NFS server.  The client continues resending the request until it receives an acknowledgement from the  server.
       Therefore,  the	server	can  crash  or power down, and come back up without any special action required by the client.	The client process
       requesting the I/O will block, but remains sensitive to signals (unless mounted with the option) until the server  recovers.   However,	if
       mounted with the option, the client process returns an error instead of waiting indefinitely.

AUTHOR

       was developed by Sun Microsystems, Inc.

SEE ALSO

       exportfs(1M), share(1M), mount(1M), mount_nfs(1M), nfsd(1M), mount(2), fstab(4), dfstab(4).

																	    nfs(7)