nfsuserd(8) [freebsd man page]

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

NAME

     nfsuserd -- load user and group information into the kernel for NFSv4 services

SYNOPSIS

     nfsuserd [-domain domain_name] [-usertimeout minutes] [-usermax max_cache_size] [-verbose] [-force] [num_servers]

DESCRIPTION

     nfsuserd loads user and group information into the kernel for NFSv4.  It must be running for NFSv4 to function correctly, either client or
     server.

     Upon startup, it loads the machines DNS domain name, plus timeout and cache size limit into the kernel. It then preloads the cache with group
     and user information, up to the cache size limit and forks off N children (default 4), that service requests from the kernel for cache
     misses. The master server is there for the sole purpose of killing off the slaves.  To stop the nfsuserd, send a SIGUSR1 to the master
     server.

     The following options are available:

     -domain domain_name
	     This option allows you to override the default DNS domain name, which is acquired by taking either the suffix on the machine's host-
	     name or, if that name is not a fully qualified host name, the canonical name as reported by getaddrinfo(3).

     -usertimeout minutes
	     Overrides the default timeout for cache entries, in minutes. If the timeout is specified as 0, cache entries never time out. The
	     longer the time out, the better the performance, but the longer it takes for replaced entries to be seen. If your user/group database
	     management system almost never re-uses the same names or id numbers, a large timeout is recommended.  The default is 1 minute.

     -usermax max_cache_size
	     Overrides the default upper bound on the cache size. The larger the cache, the more kernel memory is used, but the better the perfor-
	     mance. If your system can afford the memory use, make this the sum of the number of entries in your group and password databases.
	     The default is 200 entries.

     -verbose
	     When set, the server logs a bunch of information to syslog.

     -force  This flag option must be set to restart the daemon after it has gone away abnormally and refuses to start, because it thinks nfsuserd
	     is already running.

     num_servers
	     Specifies how many servers to create (max 20).  The default of 4 may be sufficient. You should run enough servers, so that ps(1)
	     shows almost no running time for one or two of the slaves after the system has been running for a long period. Running too few will
	     have a major performance impact, whereas running too many will only tie up some resources, such as a process table entry and swap
	     space.

SEE ALSO

     getgrent(3), getpwent(3), nfsv4(4), group(5), passwd(5), nfsd(8)

HISTORY

     The nfsuserd utility was introduced with the NFSv4 experimental subsystem in 2009.

BUGS

     The nfsuserd use getgrent(3) and getpwent(3) library calls to resolve requests and will hang if the servers handling those requests fail and
     the library functions don't return. See group(5) and passwd(5) for more information on how the databases are accessed.

BSD
								  April 25, 2009							       BSD

NFSV4(4)						   BSD Kernel Interfaces Manual 						  NFSV4(4)

NAME

     nfsv4 -- NFS Version 4 Protocol

SYNOPSIS

     experimental client and server with NFSv4 support

DESCRIPTION

     The experimental nfs client and server provides support for the NFSv4 specification; see Network File System (NFS) Version 4 Protocol RFC
     3530.  The protocol is somewhat similar to NFS Version 3, but differs in significant ways.  It uses a single Compound RPC that concatenates
     operations to-gether.  Each of these operations are similar to the RPCs of NFS Version 3.	The operations in the compound are performed in
     order, until one of them fails (returns an error) and then the RPC terminates at that point.

     It has integrated locking support, which implies that the server is no longer stateless.  As such, the NFSv4 server remains in recovery mode
     for a Grace period (always greater than the lease duration the server uses) after a reboot.  During this Grace period, clients may recover
     state but not perform other open/lock state changing operations.  To provide for correct recovery semantics, a small file described by
     stablerestart(5) is used by the server during the recovery phase.	If this file is missing, the server will not start.  If this file is lost,
     it should be recovered from backups, since creating an empty stablerestart(5) file will result in the server starting without providing a
     Grace Period for recovery.  Note that recovery only occurs when the server machine is rebooted, not when the nfsd(8) are just restarted.

     It provides several optional features not in NFS Version 3:

	   - NFS Version 4 ACLs
	   - Referrals, which redirect subtrees to other servers
	     (not yet implemented)
	   - Delegations, which allow a client to operate on a file locally

     The NFSv4 protocol does not use a separate mount protocol and assumes that the server provides a single file system tree structure, rooted at
     the point in the local file system tree specified by one or more

	   V4: <rootdir> [-sec=secflavors] [host(s) or net]

     line(s) in the exports(5) file.  (See exports(5) for details.)  The nfsd(8) allows a limited subset of operations to be performed on non-
     exported subtrees of the local file system, so that traversal of the tree to the exported subtrees is possible.  As such, the ``<rootdir>''
     can be in a non-exported file system.  However, the entire tree that is rooted at that point must be in local file systems that are of types
     that can be NFS exported.	Since the nfsv4 file system is rooted at ``<rootdir>'', setting this to anything other than ``/'' will result in
     clients being required to use different mount paths for nfsv4 than for NFS Version 2 or 3.  Unlike NFS Version 2 and 3, Version 4 allows a
     client mount to span across multiple server file systems, although not all clients are capable of doing this.

     nfsv4 uses names for users and groups instead of numbers.	On the wire, they take the form:

	   <user>@<dns.domain>

     where ``<dns.domain>'' is not the same as the DNS domain used for host name lookups, but is usually set to the same string.  Most systems set
     this ``<dns.domain>'' to the domain name part of the machine's hostname(1) by default.  However, this can normally be overridden by a command
     line option or configuration file for the daemon used to do the name<->number mapping.  On FreeBSD, the mapping daemon is called nfsuserd(8)
     and has a command line option that overrides the domain component of the machine's hostname.  For use of nfsv4, either client or server, this
     daemon must be running.  If this ``<dns.domain>'' is not set correctly or the daemon is not running, ``ls -l'' will typically report a lot of
     ``nobody'' and ``nogroup'' ownerships.

     Although uid/gid numbers are no longer used in the nfsv4 protocol, they will still be in the RPC authentication fields when running using
     AUTH_SYS (sec=sys), which is the default.	As such, in this case both the user/group name and number spaces must be consistent between the
     client and server.

     However, if you run nfsv4 with RPCSEC_GSS (sec=krb5, krb5i, krb5p), only names and KerberosV tickets will go on the wire.

SERVER SETUP

     To set up the experimental nfs server that supports nfsv4 you will need to either build a kernel with:

	   options NFSD
     and not
	   options NFSSERVER

     or start mountd(8) and nfsd(8) with the ``-e'' option to force use of the experimental server.  The nfsuserd(8) daemon must also be running.
     This will occur if

	   nfs_server_enable="YES"
	   nfsv4_server_enable="YES"
	   nfsuserd_enable="YES"

     are set in rc.conf(5).

     You will also need to add at least one ``V4:'' line to the exports(5) file and, before starting the server for the first time, create an
     empty

	   /var/db/nfs-stablerestart

     file.  The command

	   install -o root -g wheel -m 600 /dev/null /var/db/nfs-stablerestart

     executed as ``su'' should suffice.  This can only be done when the server is not running and there are no nfsv4 file system mounts against
     the server.  If this file is lost during a crash, recovery from backups is recommended.

     If the file systems you are exporting are only being accessed via nfsv4 there are a couple of sysctl(8) variables that you can change, which
     might improve performance.

     vfs.newnfs.issue_delegations
	     when set non-zero, allows the server to issue Open Delegations to clients.  These delegations permit the client to manipulate the
	     file locally on the client.  Unfortunately, at this time, client use of delegations is limited, so performance gains may not be
	     observed.	This can only be enabled when the file systems being exported to nfsv4 clients are not being accessed locally on the
	     server and, if being accessed via NFS Version 2 or 3 clients, these clients cannot be using the NLM.

     vfs.newnfs.enable_locallocks
	     can be set to 0 to disable acquisition of local byte range locks.	Disabling local locking can only be done if neither local accesses
	     to the exported file systems nor the NLM is operating on them.

     Note that Samba server access would be considered ``local access'' for the above discussion.

     To build a kernel with the experimental nfsv4 linked into it, the

	   options NFSD

     must be specified in the kernel's config(5) file.

CLIENT MOUNTS

     To do an nfsv4 mount, specify the ``nfsv4'' option on the mount_nfs(8) command line.  This will force use of the experimental client plus set
     ``tcp'' and nfsv4.

     The nfsuserd(8) must be running, as above.  If the nfsv4 server that is being mounted on supports delegations, you can start the nfscbd(8)
     daemon to handle client side callbacks.  This will occur if

	   nfsuserd_enable="YES"
	   nfscbd_enable="YES"

     are set in rc.conf(5).

     Without a functioning callback path, a server will never issue Delegations to a client.

     By default, the callback address will be set to the IP address acquired via rtalloc() in the kernel and port# 7745.  To override the default
     port#, a command line option for nfscbd(8) can be used.

     To get callbacks to work when behind a NAT gateway, a port for the callback service will need to be set up on the NAT gateway and then the
     address of the NAT gateway (host IP plus port#) will need to be set by assigning the sysctl(8) variable vfs.newnfs.callback_addr to a string
     of the form:

     N.N.N.N.N.N

     where the first 4 Ns are the host IP address and the last two are the port# in network byte order (all decimal #s in the range 0-255).

     To build a kernel with the experimental nfsv4 client linked into it, the option

	   options NFSCL

     must be specified in the kernel's config(5) file.

     Options can be specified for the nfsuserd(8) and nfscbd(8) daemons at boot time via the ``nfsuserd_flags'' and ``nfscbd_flags'' rc.conf(5)
     variables.

FILES

     /var/db/nfs-stablerestart	NFS V4 stable restart file

SEE ALSO

     stablerestart(5) mountd(8) nfscbd(8) nfsd(8) nfsdumpstate(8) nfsrevoke(8) nfsuserd(8)

BUGS

     At this time, there is no recall of delegations for local file system operations.	As such, delegations should only be enabled for file sys-
     tems that are being used soley as NFS export volumes and are not being accessed via local system calls nor services such as Samba.

BSD
								  April 30, 2009							       BSD