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RedHat 9 (Linux i386) - man page for nfs (redhat section 5)

NFS(5)				    Linux Programmer's Manual				   NFS(5)

NAME
       nfs - nfs fstab format and options

SYNOPSIS
       /etc/fstab

DESCRIPTION
       The  fstab  file contains information about which filesystems to mount where and with what
       options.  For NFS mounts, it contains the server name and  exported  server  directory  to
       mount from, the local directory that is the mount point, and the NFS specific options that
       control the way the filesystem is mounted.

       Here is an example from an /etc/fstab file from an NFS mount.

       server:/usr/local/pub	/pub   nfs    rsize=8192,wsize=8192,timeo=14,intr

   Options
       rsize=n	      The number of bytes NFS uses when reading files from an  NFS  server.   The
		      default  value is dependent on the kernel, currently 1024 bytes.	(However,
		      throughput is improved greatly by asking for rsize=8192.)

       wsize=n	      The number of bytes NFS uses when writing files  to  an  NFS  server.   The
		      default  value is dependent on the kernel, currently 1024 bytes.	(However,
		      throughput is improved greatly by asking for wsize=8192.)

       timeo=n	      The value in tenths of a second before  sending  the  first  retransmission
		      after  an  RPC  timeout.	The default value is 7 tenths of a second.  After
		      the first timeout, the timeout is doubled  after	each  successive  timeout
		      until  a maximum timeout of 60 seconds is reached or the enough retransmis-
		      sions have occured to cause a major timeout.  Then, if  the  filesystem  is
		      hard  mounted, each new timeout cascade restarts at twice the initial value
		      of the previous cascade, again doubling at each retransmission.  The  maxi-
		      mum  timeout  is	always	60  seconds.   Better  overall performance may be
		      achieved by increasing the timeout when mounting on a busy  network,  to	a
		      slow server, or through several routers or gateways.

       retrans=n      The  number  of minor timeouts and retransmissions that must occur before a
		      major timeout occurs.  The default is 3 timeouts.   When	a  major  timeout
		      occurs,  the  file operation is either aborted or a "server not responding"
		      message is printed on the console.

       acregmin=n     The minimum time in seconds that attributes of a	regular  file  should  be
		      cached before requesting fresh information from a server.  The default is 3
		      seconds.

       acregmax=n     The maximum time in seconds that attributes of a regular file can be cached
		      before  requesting fresh information from a server.  The default is 60 sec-
		      onds.

       acdirmin=n     The minimum time in seconds that attributes of a directory should be cached
		      before  requesting fresh information from a server.  The default is 30 sec-
		      onds.

       acdirmax=n     The maximum time in seconds that attributes of a directory  can  be  cached
		      before  requesting fresh information from a server.  The default is 60 sec-
		      onds.

       actimeo=n      Using actimeo sets all of acregmin, acregmax, acdirmin, and acdirmax to the
		      same value.  There is no default value.

       retry=n	      The  number of minutes to retry an NFS mount operation in the foreground or
		      background before giving up.  The default value is 10000 minutes, which  is
		      roughly one week.

       namlen=n       When  an NFS server does not support version two of the RPC mount protocol,
		      this option can be used to specify the maximum length of a filename that is
		      supported  on  the  remote  filesystem.	This is used to support the POSIX
		      pathconf functions.  The default is 255 characters.

       port=n	      The numeric value of the port to connect to the NFS server on.  If the port
		      number  is  0 (the default) then query the remote host's portmapper for the
		      port number to use.  If the remote host's NFS daemon is not registered with
		      its portmapper, the standard NFS port number 2049 is used instead.

       mountport=n    The numeric value of the mountd port.

       mounthost=name The name of the host running mountd .

       mountprog=n    Use  an  alternate  RPC  program	number to contact the mount daemon on the
		      remote host.  This option is useful for hosts that  can  run  multiple  NFS
		      servers.	 The default value is 100005 which is the standard RPC mount dae-
		      mon program number.

       mountvers=n    Use an alternate RPC version number to contact  the  mount  daemon  on  the
		      remote  host.   This  option  is useful for hosts that can run multiple NFS
		      servers.	The default value is version 1.

       nfsprog=n      Use an alternate RPC program number to contact the NFS daemon on the remote
		      host.   This  option is useful for hosts that can run multiple NFS servers.
		      The default value is 100003 which is the standard RPC  NFS  daemon  program
		      number.

       nfsvers=n      Use an alternate RPC version number to contact the NFS daemon on the remote
		      host.  This option is useful for hosts that can run multiple  NFS  servers.
		      The default value is version 2.

       nolock	      Disable NFS locking. Do not start lockd.	This has to be used with some old
		      NFS servers that don't support locking.

       bg	      If the first NFS mount attempt times out, retry  the  mount  in  the  back-
		      ground.	After a mount operation is backgrounded, all subsequent mounts on
		      the same	NFS  server  will  be  backgrounded  immediately,  without  first
		      attempting  the  mount.	A missing mount point is treated as a timeout, to
		      allow for nested NFS mounts.

       fg	      If the first NFS mount attempt times out, retry  the  mount  in  the  fore-
		      ground.	This  is  the  complement  of the bg option, and also the default
		      behavior.

       soft	      If an NFS file operation has a major timeout then report an  I/O	error  to
		      the  calling  program.  The default is to continue retrying NFS file opera-
		      tions indefinitely.

       hard	      If an NFS file operation has  a  major  timeout  then  report  "server  not
		      responding" on the console and continue retrying indefinitely.  This is the
		      default.

       intr	      If an NFS file operation has a major timeout and it is hard  mounted,  then
		      allow  signals  to interupt the file operation and cause it to return EINTR
		      to the calling program.  The default is to not allow file operations to  be
		      interrupted.

       posix	      Mount  the  NFS  filesystem  using  POSIX  semantics.   This  allows an NFS
		      filesystem to properly support the POSIX pathconf command by  querying  the
		      mount  server for the maximum length of a filename.  To do this, the remote
		      host must support version two of the RPC mount protocol.	Many NFS  servers
		      support only version one.

       nocto	      Suppress the retrieval of new attributes when creating a file.

       noac	      Disable  all  forms  of attribute caching entirely.  This extracts a server
		      performance penalty but it allows two different NFS clients to get  reason-
		      able good results when both clients are actively writing to common filesys-
		      tem on the server.

       tcp	      Mount the NFS filesystem using the TCP protocol instead of the default  UDP
		      protocol.  Many NFS servers only support UDP.

       udp	      Mount the NFS filesystem using the UDP protocol.	This is the default.

       All of the non-value options have corresponding nooption forms.	For example, nointr means
       don't allow file operations to be interrupted.

FILES
       /etc/fstab

SEE ALSO
       fstab(5), mount(8), umount(8), exports(5)

AUTHOR
       "Rick Sladkey" <jrs@world.std.com>

BUGS
       The posix, and nocto options are parsed by mount but currently are silently ignored.

       The tcp and namlen options are implemented but are not currently supported  by  the  Linux
       kernel.

       The umount command should notify the server when an NFS filesystem is unmounted.

Linux 0.99				 20 November 1993				   NFS(5)


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