1.\" Copyright (c) 1989, 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 3. Neither the name of the University nor the names of its contributors 13.\" may be used to endorse or promote products derived from this software 14.\" without specific prior written permission. 15.\" 16.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 17.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 20.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26.\" SUCH DAMAGE. 27.\" 28.\" @(#)nfsd.8 8.4 (Berkeley) 3/29/95 29.\" $FreeBSD$ 30.\" 31.Dd June 30, 2018 32.Dt NFSD 8 33.Os 34.Sh NAME 35.Nm nfsd 36.Nd remote 37.Tn NFS 38server 39.Sh SYNOPSIS 40.Nm 41.Op Fl ardute 42.Op Fl n Ar num_servers 43.Op Fl h Ar bindip 44.Op Fl p Ar pnfs_setup 45.Op Fl m Ar mirror_level 46.Op Fl Fl maxthreads Ar max_threads 47.Op Fl Fl minthreads Ar min_threads 48.Sh DESCRIPTION 49The 50.Nm 51utility runs on a server machine to service 52.Tn NFS 53requests from client machines. 54At least one 55.Nm 56must be running for a machine to operate as a server. 57.Pp 58Unless otherwise specified, eight servers per CPU for 59.Tn UDP 60transport are started. 61.Pp 62The following options are available: 63.Bl -tag -width Ds 64.It Fl r 65Register the 66.Tn NFS 67service with 68.Xr rpcbind 8 69without creating any servers. 70This option can be used along with the 71.Fl u 72or 73.Fl t 74options to re-register NFS if the rpcbind server is restarted. 75.It Fl d 76Unregister the 77.Tn NFS 78service with 79.Xr rpcbind 8 80without creating any servers. 81.It Fl n Ar threads 82Specifies how many servers to create. This option is equivalent to specifying 83.Fl Fl maxthreads 84and 85.Fl Fl minthreads 86with their respective arguments to 87.Ar threads . 88.It Fl Fl maxthreads Ar threads 89Specifies the maximum servers that will be kept around to service requests. 90.It Fl Fl minthreads Ar threads 91Specifies the minimum servers that will be kept around to service requests. 92.It Fl h Ar bindip 93Specifies which IP address or hostname to bind to on the local host. 94This option is recommended when a host has multiple interfaces. 95Multiple 96.Fl h 97options may be specified. 98.It Fl a 99Specifies that nfsd should bind to the wildcard IP address. 100This is the default if no 101.Fl h 102options are given. 103It may also be specified in addition to any 104.Fl h 105options given. 106Note that NFS/UDP does not operate properly when 107bound to the wildcard IP address whether you use -a or do not use -h. 108.It Fl p Ar pnfs_setup 109Enables pNFS support in the server and specifies the information that the 110daemon needs to start it. 111This option can only be used on one server and specifies that this server 112will be the MetaData Server (MDS) for the pNFS service. 113This can only be done if there is at least one FreeBSD system configured 114as a Data Server (DS) for it to use. 115.Pp 116The 117.Ar pnfs_setup 118string is a set of fields separated by ',' characters: 119.Bl -tag -width Ds 120Each of these fields specifies one Data Server. 121It consists of a server hostname, followed by a ':' 122and the directory path where the DS's data storage file system is mounted on 123this MDS server. 124At this time, only IPv4 addresses are supported by the interface to the kernel, 125so the 126.Dq server hostname 127must resolve to an IPv4 address and support mounts on that address. 128This needs to be extended to support IPv6 addresses in the near future. 129This can optionally be followed by a '#' and the mds_path, which is the 130directory path for an exported file system on this MDS. 131If this is specified, it means that this DS is to be used to store data 132files for this mds_path file system only. 133If this optional component does not exist, the DS will be used to store data 134files for all exported MDS file systems. 135The DS storage file systems must be mounted on this system before the 136.Nm 137is started with this option specified. 138.br 139For example: 140.sp 141nfsv4-data0:/data0,nfsv4-data1:/data1 142.sp 143would specify two DS servers called nfsv4-data0 and nfsv4-data1 that comprise 144the data storage component of the pNFS service. 145These two DSs would be used to store data files for all exported file systems 146on this MDS. 147The directories 148.Dq /data0 149and 150.Dq /data1 151are where the data storage servers exported 152storage directories are mounted on this system (which will act as the MDS). 153.br 154Whereas, for the example: 155.sp 156nfsv4-data0:/data0#/export1,nfsv4-data1:/data1#/export2 157.sp 158would specify two DSs as above, however nfsv4-data0 will be used to store 159data files for 160.Dq /export1 161and nfsv4-data1 will be used to store data files for 162.Dq /export2 . 163.El 164.It Fl m Ar mirror_level 165This option is only meaningful when used with the 166.Fl p 167option. 168It specifies the 169.Dq mirror_level , 170which defines how many of the DSs will 171have a copy of a file's data storage file. 172The default of one implies no mirroring of data storage files on the DSs. 173The 174.Dq mirror_level 175would normally be set to 2 to enable mirroring, but 176can be as high as NFSDEV_MAXMIRRORS. 177There must be at least 178.Dq mirror_level 179DSs for each exported file system on the MDS, as specified in the 180.Fl p 181option. 182This implies that, for the above example using "#/export1" and "#/export2", 183mirroring cannot be done. 184There would need to be two DS entries for each of "#/export1" and "#/export2" 185in order to support a 186.Dq mirror_level 187of two. 188.Pp 189If mirroring is enabled, the server must use the Flexible File 190layout. 191If mirroring is not enabled, the server will use the File layout 192by default, but this default can be changed to the Flexible File layout if the 193.Xr sysctl 1 194vfs.nfsd.default_flexfile 195is set non-zero. 196.It Fl t 197Serve 198.Tn TCP NFS 199clients. 200.It Fl u 201Serve 202.Tn UDP NFS 203clients. 204.It Fl e 205Ignored; included for backward compatibility. 206.El 207.Pp 208For example, 209.Dq Li "nfsd -u -t -n 6" 210serves 211.Tn UDP 212and 213.Tn TCP 214transports using six daemons. 215.Pp 216A server should run enough daemons to handle 217the maximum level of concurrency from its clients, 218typically four to six. 219.Pp 220The 221.Nm 222utility listens for service requests at the port indicated in the 223.Tn NFS 224server specification; see 225.%T "Network File System Protocol Specification" , 226RFC1094, 227.%T "NFS: Network File System Version 3 Protocol Specification" , 228RFC1813, 229.%T "Network File System (NFS) Version 4 Protocol" , 230RFC3530 and 231.%T "Network File System (NFS) Version 4 Minor Version 1 Protocol" , 232RFC5661. 233.Pp 234If 235.Nm 236detects that 237.Tn NFS 238is not loaded in the running kernel, it will attempt 239to load a loadable kernel module containing 240.Tn NFS 241support using 242.Xr kldload 2 . 243If this fails, or no 244.Tn NFS 245KLD is available, 246.Nm 247will exit with an error. 248.Pp 249If 250.Nm 251is to be run on a host with multiple interfaces or interface aliases, use 252of the 253.Fl h 254option is recommended. 255If you do not use the option NFS may not respond to 256UDP packets from the same IP address they were sent to. 257Use of this option 258is also recommended when securing NFS exports on a firewalling machine such 259that the NFS sockets can only be accessed by the inside interface. 260The 261.Nm ipfw 262utility 263would then be used to block nfs-related packets that come in on the outside 264interface. 265.Pp 266If the server has stopped servicing clients and has generated a console message 267like 268.Dq Li "nfsd server cache flooded..." , 269the value for vfs.nfsd.tcphighwater needs to be increased. 270This should allow the server to again handle requests without a reboot. 271Also, you may want to consider decreasing the value for 272vfs.nfsd.tcpcachetimeo to several minutes (in seconds) instead of 12 hours 273when this occurs. 274.Pp 275Unfortunately making vfs.nfsd.tcphighwater too large can result in the mbuf 276limit being reached, as indicated by a console message 277like 278.Dq Li "kern.ipc.nmbufs limit reached" . 279If you cannot find values of the above 280.Nm sysctl 281values that work, you can disable the DRC cache for TCP by setting 282vfs.nfsd.cachetcp to 0. 283.Pp 284The 285.Nm 286utility has to be terminated with 287.Dv SIGUSR1 288and cannot be killed with 289.Dv SIGTERM 290or 291.Dv SIGQUIT . 292The 293.Nm 294utility needs to ignore these signals in order to stay alive as long 295as possible during a shutdown, otherwise loopback mounts will 296not be able to unmount. 297If you have to kill 298.Nm 299just do a 300.Dq Li "kill -USR1 <PID of master nfsd>" 301.Sh EXIT STATUS 302.Ex -std 303.Sh SEE ALSO 304.Xr nfsstat 1 , 305.Xr kldload 2 , 306.Xr nfssvc 2 , 307.Xr nfsv4 4 , 308.Xr pnfs 4 , 309.Xr exports 5 , 310.Xr stablerestart 5 , 311.Xr gssd 8 , 312.Xr ipfw 8 , 313.Xr mountd 8 , 314.Xr nfsiod 8 , 315.Xr nfsrevoke 8 , 316.Xr nfsuserd 8 , 317.Xr rpcbind 8 318.Sh HISTORY 319The 320.Nm 321utility first appeared in 322.Bx 4.4 . 323.Sh BUGS 324If 325.Nm 326is started when 327.Xr gssd 8 328is not running, it will service AUTH_SYS requests only. To fix the problem 329you must kill 330.Nm 331and then restart it, after the 332.Xr gssd 8 333is running. 334.Pp 335If mirroring is enabled via the 336.Fl m 337option and there are Linux clients doing NFSv4.1 mounts, those clients 338need to be patched to support the 339.Dq tightly coupled 340variant of 341the Flexible File layout or the 342.Xr sysctl 1 343vfs.nfsd.flexlinuxhack 344must be set to one on the MDS as a workaround. 345