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

     nfsd -- remote NFS	server

     nfsd [-ardute] [-n	num_servers] [-h bindip] [--maxthreads max_threads]
	  [--minthreads	min_threads]

     The nfsd utility runs on a	server machine to service NFS requests from
     client machines.  At least	one nfsd must be running for a machine to op-
     erate as a	server.

     Unless otherwise specified, eight servers per CPU for UDP transport are

     The following options are available:

     -r	     Register the NFS service with rpcbind(8) without creating any
	     servers.  This option can be used along with the -u or -t options
	     to	re-register NFS	if the rpcbind server is restarted.

     -d	     Unregister	the NFS	service	with rpcbind(8)	without	creating any

     -n	threads
	     Specifies how many	servers	to create.  This option	is equivalent
	     to	specifying --maxthreads	and --minthreads with their respective
	     arguments to threads.

     --maxthreads threads
	     Specifies the maximum servers that	will be	kept around to service

     --minthreads threads
	     Specifies the minimum servers that	will be	kept around to service

     -h	bindip
	     Specifies which IP	address	or hostname to bind to on the local
	     host.  This option	is recommended when a host has multiple	inter-
	     faces.  Multiple -h options may be	specified.

     -a	     Specifies that nfsd should	bind to	the wildcard IP	address.  This
	     is	the default if no -h options are given.	 It may	also be	speci-
	     fied in addition to any -h	options	given.	Note that NFS/UDP does
	     not operate properly when bound to	the wildcard IP	address
	     whether you use -a	or do not use -h.

     -t	     Serve TCP NFS clients.

     -u	     Serve UDP NFS clients.

     -e	     Ignored; included for backward compatibility.

     For example, "nfsd	-u -t -n 6" serves UDP and TCP transports using	six

     A server should run enough	daemons	to handle the maximum level of concur-
     rency from	its clients, typically four to six.

     The nfsd utility listens for service requests at the port indicated in
     the NFS server specification; see Network File System Protocol
     Specification, RFC1094, NFS: Network File System Version 3	Protocol
     Specification, RFC1813 and	Network	File System (NFS) Version 4 Protocol,

     If	nfsd detects that NFS is not loaded in the running kernel, it will at-
     tempt to load a loadable kernel module containing NFS support using
     kldload(2).  If this fails, or no NFS KLD is available, nfsd will exit
     with an error.

     If	nfsd is	to be run on a host with multiple interfaces or	interface
     aliases, use of the -h option is recommended.  If you do not use the op-
     tion NFS may not respond to UDP packets from the same IP address they
     were sent to.  Use	of this	option is also recommended when	securing NFS
     exports on	a firewalling machine such that	the NFS	sockets	can only be
     accessed by the inside interface.	The ipfw utility would then be used to
     block nfs-related packets that come in on the outside interface.

     If	the server has stopped servicing clients and has generated a console
     message like "nfsd	server cache flooded...", the value for
     vfs.nfsd.tcphighwater needs to be increased.  This	should allow the
     server to again handle requests without a reboot.	Also, you may want to
     consider decreasing the value for vfs.nfsd.tcpcachetimeo to several min-
     utes (in seconds) instead of 12 hours when	this occurs.

     Unfortunately making vfs.nfsd.tcphighwater	too large can result in	the
     mbuf limit	being reached, as indicated by a console message like
     "kern.ipc.nmbufs limit reached".  If you cannot find values of the	above
     sysctl values that	work, you can disable the DRC cache for	TCP by setting
     vfs.nfsd.cachetcp to 0.

     The nfsd utility has to be	terminated with	SIGUSR1	and cannot be killed
     with SIGTERM or SIGQUIT.  The nfsd	utility	needs to ignore	these signals
     in	order to stay alive as long as possible	during a shutdown, otherwise
     loopback mounts will not be able to unmount.  If you have to kill nfsd
     just do a "kill -USR1 <PID	of master nfsd>"

     The nfsd utility exits 0 on success, and >0 if an error occurs.

     nfsstat(1), kldload(2), nfssvc(2),	nfsv4(4), exports(5),
     stablerestart(5), gssd(8),	ipfw(8), mountd(8), nfsiod(8), nfsrevoke(8),
     nfsuserd(8), rpcbind(8)

     The nfsd utility first appeared in	4.4BSD.

     If	nfsd is	started	when gssd(8) is	not running, it	will service AUTH_SYS
     requests only. To fix the problem you must	kill nfsd and then restart it,
     after the gssd(8) is running.

BSD				April 25, 2015				   BSD


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