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 February 14, 2019 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 V Ar virtual_hostname 47.Op Fl Fl maxthreads Ar max_threads 48.Op Fl Fl minthreads Ar min_threads 49.Sh DESCRIPTION 50The 51.Nm 52utility runs on a server machine to service 53.Tn NFS 54requests from client machines. 55At least one 56.Nm 57must be running for a machine to operate as a server. 58.Pp 59Unless otherwise specified, eight servers per CPU for 60.Tn UDP 61transport are started. 62.Pp 63The following options are available: 64.Bl -tag -width Ds 65.It Fl r 66Register the 67.Tn NFS 68service with 69.Xr rpcbind 8 70without creating any servers. 71This option can be used along with the 72.Fl u 73or 74.Fl t 75options to re-register NFS if the rpcbind server is restarted. 76.It Fl d 77Unregister the 78.Tn NFS 79service with 80.Xr rpcbind 8 81without creating any servers. 82.It Fl V Ar virtual_hostname 83Specifies a hostname to be used as a principal name, instead of 84the default hostname. 85.It Fl n Ar threads 86Specifies how many servers to create. This option is equivalent to specifying 87.Fl Fl maxthreads 88and 89.Fl Fl minthreads 90with their respective arguments to 91.Ar threads . 92.It Fl Fl maxthreads Ar threads 93Specifies the maximum servers that will be kept around to service requests. 94.It Fl Fl minthreads Ar threads 95Specifies the minimum servers that will be kept around to service requests. 96.It Fl h Ar bindip 97Specifies which IP address or hostname to bind to on the local host. 98This option is recommended when a host has multiple interfaces. 99Multiple 100.Fl h 101options may be specified. 102.It Fl a 103Specifies that nfsd should bind to the wildcard IP address. 104This is the default if no 105.Fl h 106options are given. 107It may also be specified in addition to any 108.Fl h 109options given. 110Note that NFS/UDP does not operate properly when 111bound to the wildcard IP address whether you use -a or do not use -h. 112.It Fl p Ar pnfs_setup 113Enables pNFS support in the server and specifies the information that the 114daemon needs to start it. 115This option can only be used on one server and specifies that this server 116will be the MetaData Server (MDS) for the pNFS service. 117This can only be done if there is at least one FreeBSD system configured 118as a Data Server (DS) for it to use. 119.Pp 120The 121.Ar pnfs_setup 122string is a set of fields separated by ',' characters: 123.Bl -tag -width Ds 124Each of these fields specifies one DS. 125It consists of a server hostname, followed by a ':' 126and the directory path where the DS's data storage file system is mounted on 127this MDS server. 128This can optionally be followed by a '#' and the mds_path, which is the 129directory path for an exported file system on this MDS. 130If this is specified, it means that this DS is to be used to store data 131files for this mds_path file system only. 132If this optional component does not exist, the DS will be used to store data 133files for all exported MDS file systems. 134The DS storage file systems must be mounted on this system before the 135.Nm 136is started with this option specified. 137.br 138For example: 139.sp 140nfsv4-data0:/data0,nfsv4-data1:/data1 141.sp 142would specify two DS servers called nfsv4-data0 and nfsv4-data1 that comprise 143the data storage component of the pNFS service. 144These two DSs would be used to store data files for all exported file systems 145on this MDS. 146The directories 147.Dq /data0 148and 149.Dq /data1 150are where the data storage servers exported 151storage directories are mounted on this system (which will act as the MDS). 152.br 153Whereas, for the example: 154.sp 155nfsv4-data0:/data0#/export1,nfsv4-data1:/data1#/export2 156.sp 157would specify two DSs as above, however nfsv4-data0 will be used to store 158data files for 159.Dq /export1 160and nfsv4-data1 will be used to store data files for 161.Dq /export2 . 162.El 163.sp 164When using IPv6 addresses for DSs 165be wary of using link local addresses. 166The IPv6 address for the DS is sent to the client and there is no scope 167zone in it. 168As such, a link local address may not work for a pNFS client to DS 169TCP connection. 170When parsed, 171.Nm 172will only use a link local address if it is the only address returned by 173.Xr getaddrinfo 3 174for the DS hostname. 175.It Fl m Ar mirror_level 176This option is only meaningful when used with the 177.Fl p 178option. 179It specifies the 180.Dq mirror_level , 181which defines how many of the DSs will 182have a copy of a file's data storage file. 183The default of one implies no mirroring of data storage files on the DSs. 184The 185.Dq mirror_level 186would normally be set to 2 to enable mirroring, but 187can be as high as NFSDEV_MAXMIRRORS. 188There must be at least 189.Dq mirror_level 190DSs for each exported file system on the MDS, as specified in the 191.Fl p 192option. 193This implies that, for the above example using "#/export1" and "#/export2", 194mirroring cannot be done. 195There would need to be two DS entries for each of "#/export1" and "#/export2" 196in order to support a 197.Dq mirror_level 198of two. 199.Pp 200If mirroring is enabled, the server must use the Flexible File 201layout. 202If mirroring is not enabled, the server will use the File layout 203by default, but this default can be changed to the Flexible File layout if the 204.Xr sysctl 1 205vfs.nfsd.default_flexfile 206is set non-zero. 207.It Fl t 208Serve 209.Tn TCP NFS 210clients. 211.It Fl u 212Serve 213.Tn UDP NFS 214clients. 215.It Fl e 216Ignored; included for backward compatibility. 217.El 218.Pp 219For example, 220.Dq Li "nfsd -u -t -n 6" 221serves 222.Tn UDP 223and 224.Tn TCP 225transports using six daemons. 226.Pp 227A server should run enough daemons to handle 228the maximum level of concurrency from its clients, 229typically four to six. 230.Pp 231The 232.Nm 233utility listens for service requests at the port indicated in the 234.Tn NFS 235server specification; see 236.%T "Network File System Protocol Specification" , 237RFC1094, 238.%T "NFS: Network File System Version 3 Protocol Specification" , 239RFC1813, 240.%T "Network File System (NFS) Version 4 Protocol" , 241RFC3530 and 242.%T "Network File System (NFS) Version 4 Minor Version 1 Protocol" , 243RFC5661. 244.Pp 245If 246.Nm 247detects that 248.Tn NFS 249is not loaded in the running kernel, it will attempt 250to load a loadable kernel module containing 251.Tn NFS 252support using 253.Xr kldload 2 . 254If this fails, or no 255.Tn NFS 256KLD is available, 257.Nm 258will exit with an error. 259.Pp 260If 261.Nm 262is to be run on a host with multiple interfaces or interface aliases, use 263of the 264.Fl h 265option is recommended. 266If you do not use the option NFS may not respond to 267UDP packets from the same IP address they were sent to. 268Use of this option 269is also recommended when securing NFS exports on a firewalling machine such 270that the NFS sockets can only be accessed by the inside interface. 271The 272.Nm ipfw 273utility 274would then be used to block nfs-related packets that come in on the outside 275interface. 276.Pp 277If the server has stopped servicing clients and has generated a console message 278like 279.Dq Li "nfsd server cache flooded..." , 280the value for vfs.nfsd.tcphighwater needs to be increased. 281This should allow the server to again handle requests without a reboot. 282Also, you may want to consider decreasing the value for 283vfs.nfsd.tcpcachetimeo to several minutes (in seconds) instead of 12 hours 284when this occurs. 285.Pp 286Unfortunately making vfs.nfsd.tcphighwater too large can result in the mbuf 287limit being reached, as indicated by a console message 288like 289.Dq Li "kern.ipc.nmbufs limit reached" . 290If you cannot find values of the above 291.Nm sysctl 292values that work, you can disable the DRC cache for TCP by setting 293vfs.nfsd.cachetcp to 0. 294.Pp 295The 296.Nm 297utility has to be terminated with 298.Dv SIGUSR1 299and cannot be killed with 300.Dv SIGTERM 301or 302.Dv SIGQUIT . 303The 304.Nm 305utility needs to ignore these signals in order to stay alive as long 306as possible during a shutdown, otherwise loopback mounts will 307not be able to unmount. 308If you have to kill 309.Nm 310just do a 311.Dq Li "kill -USR1 <PID of master nfsd>" 312.Sh EXIT STATUS 313.Ex -std 314.Sh SEE ALSO 315.Xr nfsstat 1 , 316.Xr kldload 2 , 317.Xr nfssvc 2 , 318.Xr nfsv4 4 , 319.Xr pnfs 4 , 320.Xr pnfsserver 4 , 321.Xr exports 5 , 322.Xr stablerestart 5 , 323.Xr gssd 8 , 324.Xr ipfw 8 , 325.Xr mountd 8 , 326.Xr nfsiod 8 , 327.Xr nfsrevoke 8 , 328.Xr nfsuserd 8 , 329.Xr rpcbind 8 330.Sh HISTORY 331The 332.Nm 333utility first appeared in 334.Bx 4.4 . 335.Sh BUGS 336If 337.Nm 338is started when 339.Xr gssd 8 340is not running, it will service AUTH_SYS requests only. To fix the problem 341you must kill 342.Nm 343and then restart it, after the 344.Xr gssd 8 345is running. 346.Pp 347If mirroring is enabled via the 348.Fl m 349option and there are Linux clients doing NFSv4.1 mounts, those clients 350need to be patched to support the 351.Dq tightly coupled 352variant of 353the Flexible File layout or the 354.Xr sysctl 1 355vfs.nfsd.flexlinuxhack 356must be set to one on the MDS as a workaround. 357