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MOUNT_NFS4(8)		  BSD System Manager's Manual		 MOUNT_NFS4(8)

     mount_nfs4	-- mount NFSv4 file systems

     mount_nfs4	[-NPTUbcdiLls] [-D deadthresh] [-I readdirsize]	[-R retrycnt]
		[-a maxreadahead] [-g maxgroups] [-o options] [-r readsize]
		[-t timeout] [-w writesize] [-x	retrans] rhost:path node

     The mount_nfs4 utility calls the mount(2) system call to prepare and
     graft a remote NFSv4 file system (rhost:path) on to the file system tree
     at	the point node.	 This command is normally executed by mount(8).	 It
     implements	the NFSv4 protocol as described	in RFC 3530, NFS version 4

     If	the server becomes unresponsive	while an NFSv4 file system is mounted,
     any new or	outstanding file operations on that file system	will hang un-
     interruptibly until the server comes back.	 To modify this	default	behav-
     iour, see the -i and -s flags.

     The options are:

     -D	     Set the "dead server threshold" to	the specified number of	round
	     trip timeout intervals before a "server not responding" message
	     is	displayed.

     -I	     Set the readdir read size to the specified	value.	The value
	     should normally be	a multiple of DIRBLKSIZ	that is	<= the read
	     size for the mount.

     -N	     Do	not use	a reserved socket port number (see below).

     -P	     Use a reserved socket port	number.	 This flag is obsolete,	and
	     only retained for compatibility reasons.  Reserved	port numbers
	     are used by default now.  (For the	rare case where	the client has
	     a trusted root account but	untrustworthy users and	the network
	     cables are	in secure areas	this does help,	but for	normal desktop
	     clients this does not apply.)

     -R	     Set the mount retry count to the specified	value.	The default is
	     a retry count of zero, which means	to keep	retrying forever.
	     There is a	60 second delay	between	each attempt.

     -T	     Use TCP transport.	This is	the default.

     -U	     Force the mount protocol to use UDP transport.  This is not sup-
	     ported by the version 4 protocol and is provided only for debug-
	     ging purposes.

     -a	     Set the read-ahead	count to the specified value.  This may	be in
	     the range of 0 - 4, and determines	how many blocks	will be	read
	     ahead when	a large	file is	being read sequentially.  Trying a
	     value greater than	1 for this is suggested	for mounts with	a
	     large bandwidth * delay product.

     -b	     If	an initial attempt to contact the server fails,	fork off a
	     child to keep trying the mount in the background.	Useful for
	     fstab(5), where the file system mount is not critical to multi-
	     user operation.

     -i	     Make the mount interruptible, which implies that file system
	     calls that	are delayed due	to an unresponsive server will fail
	     with EINTR	when a termination signal is posted for	the process.

     -o	     Options are specified with	a -o flag followed by a	comma sepa-
	     rated string of options.  See the mount(8)	man page for possible
	     options and their meanings.  The following	NFS specific options
	     are also available:

		     Use specified port	number for NFSv4 requests.  The	de-
		     fault is to use port 2049.	 Set this to 0 to query	the
		     portmapper	for the	NFSv4 port.




		     When attributes of	files are cached, a timeout calculated
		     to	determine whether a given cache	entry has expired.
		     These four	values determine the upper and lower bounds of
		     the timeouts for "directory" attributes and "regular"
		     (ie: everything else).  The default values	are 3 -> 60
		     seconds for regular files,	and 30 -> 60 seconds for di-
		     rectories.	 The algorithm to calculate the	timeout	is
		     based on the age of the file.  The	older the file,	the
		     longer the	cache is considered valid, subject to the lim-
		     its above.

	     noinet4, noinet6
		     Disables AF_INET or AF_INET6 connections.	Useful for
		     hosts that	have both an A record and an AAAA record for
		     the same name.

     -s	     A soft mount, which implies that file system calls	will fail af-
	     ter retrycnt round	trip timeout intervals.

     -t	     Set the initial retransmit	timeout	to the specified value.	 May
	     be	useful for fine	tuning UDP mounts over internetworks with high
	     packet loss rates or an overloaded	server.	 Try increasing	the
	     interval if nfsstat(1) shows high retransmit rates	while the file
	     system is active or reducing the value if there is	a low retrans-
	     mit rate but long response	delay observed.	 (Normally, the	-d op-
	     tion should be specified when using this option to	manually tune
	     the timeout interval.)

     -x	     Set the retransmit	timeout	count for soft mounts to the specified

     mount(2), unmount(2), fstab(5), idmapd(8),	mount(8), mount_nfs(8),
     nfsd(8), nfsiod(8)

     This version of the NFSv4 client, while functional, is a long way from
     compliance	with RFC 3530. It lacks	lock state, reboot recovery, delega-
     tion, gss,	and many other mandatory items from the	RFC.

BSD			       November	14, 2003			   BSD


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