.\" Copyright (c) 1989, 1991, 1993 .\" The Regents of the University of California. All rights reserved. .\" .\" Redistribution and use in source and binary forms, with or without .\" modification, are permitted provided that the following conditions .\" are met: .\" 1. Redistributions of source code must retain the above copyright .\" notice, this list of conditions and the following disclaimer. .\" 2. Redistributions in binary form must reproduce the above copyright .\" notice, this list of conditions and the following disclaimer in the .\" documentation and/or other materials provided with the distribution. .\" 4. Neither the name of the University nor the names of its contributors .\" may be used to endorse or promote products derived from this software .\" without specific prior written permission. .\" .\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE .\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF .\" SUCH DAMAGE. .\" .\" @(#)nfsd.8 8.4 (Berkeley) 3/29/95 .\" $FreeBSD$ .\" .Dd January 1, 2015 .Dt NFSD 8 .Os .Sh NAME .Nm nfsd .Nd remote .Tn NFS server .Sh SYNOPSIS .Nm .Op Fl arduteo .Op Fl n Ar num_servers .Op Fl h Ar bindip .Op Fl Fl maxthreads Ar max_threads .Op Fl Fl minthreads Ar min_threads .Sh DESCRIPTION The .Nm utility runs on a server machine to service .Tn NFS requests from client machines. At least one .Nm must be running for a machine to operate as a server. .Pp Unless otherwise specified, eight servers per CPU for .Tn UDP transport are started. .Pp The following options are available: .Bl -tag -width Ds .It Fl r Register the .Tn NFS service with .Xr rpcbind 8 without creating any servers. This option can be used along with the .Fl u or .Fl t options to re-register NFS if the rpcbind server is restarted. .It Fl d Unregister the .Tn NFS service with .Xr rpcbind 8 without creating any servers. .It Fl n Ar threads Specifies how many servers to create. This option is equivalent to specifying .Fl Fl maxthreads and .Fl Fl minthreads with their respective arguments to .Ar threads . .It Fl Fl maxthreads Ar threads Specifies the maximum servers that will be kept around to service requests. .It Fl Fl minthreads Ar threads Specifies the minimum servers that will be kept around to service requests. .It Fl h Ar bindip Specifies which IP address or hostname to bind to on the local host. This option is recommended when a host has multiple interfaces. Multiple .Fl h options may be specified. .It Fl a Specifies that nfsd should bind to the wildcard IP address. This is the default if no .Fl h options are given. It may also be specified in addition to any .Fl 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. .It Fl t Serve .Tn TCP NFS clients. .It Fl u Serve .Tn UDP NFS clients. .It Fl e The new NFS server that includes NFSv4 support is now the default, so this option is now a no-op and should be considered deprecated. .It Fl o Forces the use of the old NFS server that does not include NFSv4 support in it. .El .Pp For example, .Dq Li "nfsd -u -t -n 6" serves .Tn UDP and .Tn TCP transports using six daemons. .Pp A server should run enough daemons to handle the maximum level of concurrency from its clients, typically four to six. .Pp The .Nm utility listens for service requests at the port indicated in the .Tn NFS server specification; see .%T "Network File System Protocol Specification" , RFC1094, .%T "NFS: Network File System Version 3 Protocol Specification" , RFC1813 and .%T "Network File System (NFS) Version 4 Protocol" , RFC3530. .Pp If .Nm detects that .Tn NFS is not loaded in the running kernel, it will attempt to load a loadable kernel module containing .Tn NFS support using .Xr kldload 2 . If this fails, or no .Tn NFS KLD is available, .Nm will exit with an error. .Pp If .Nm is to be run on a host with multiple interfaces or interface aliases, use of the .Fl h option is recommended. If you do not use the option 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 .Nm ipfw utility would then be used to block nfs-related packets that come in on the outside interface. .Pp If the server has stopped servicing clients and has generated a console message like .Dq Li "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 minutes (in seconds) instead of 12 hours when this occurs. .Pp Unfortunately making vfs.nfsd.tcphighwater too large can result in the mbuf limit being reached, as indicated by a console message like .Dq Li "kern.ipc.nmbufs limit reached" . If you cannot find values of the above .Nm sysctl values that work, you can disable the DRC cache for TCP by setting vfs.nfsd.cachetcp to 0. .Pp The .Nm utility has to be terminated with .Dv SIGUSR1 and cannot be killed with .Dv SIGTERM or .Dv SIGQUIT . The .Nm 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 .Nm just do a .Dq Li "kill -USR1 " .Sh EXIT STATUS .Ex -std .Sh SEE ALSO .Xr nfsstat 1 , .Xr kldload 2 , .Xr nfssvc 2 , .Xr nfsv4 4 , .Xr exports 5 , .Xr stablerestart 5 , .Xr gssd 8 , .Xr ipfw 8 , .Xr mountd 8 , .Xr nfsiod 8 , .Xr nfsrevoke 8 , .Xr nfsuserd 8 , .Xr rpcbind 8 .Sh HISTORY The .Nm utility first appeared in .Bx 4.4 . .Sh BUGS If .Nm is started when .Xr gssd 8 is not running, it will service AUTH_SYS requests only. To fix the problem you must kill .Nm and then restart it, after the .Xr gssd 8 is running.