mount_nfs man page on SmartOS

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       mount_nfs - mount remote NFS resources

       mount [-F nfs] [generic_options] [-o specific_options] [-O] resource

       mount [-F nfs] [generic_options] [-o specific_options] [-O] mount_point

       mount [-F nfs] [generic_options] [-o specific_options]
	    [-O] resource mount_point

       The  mount utility attaches a named resource to the file system hierar‐
       chy at the pathname location mount_point, which must already exist.  If
       mount_point has any contents prior to the mount operation, the contents
       remain hidden until the resource is once again unmounted.

       mount_nfs starts the lockd(1M) and statd(1M) daemons if	they  are  not
       already running.

       If the resource is listed in the /etc/vfstab file, the command line can
       specify either resource or mount_point, and mount consults  /etc/vfstab
       for more information. If the -F option is omitted, mount takes the file
       system type from /etc/vfstab.

       If the resource is not listed in the /etc/vfstab file, then the command
       line must specify both the resource and the mount_point.

       host  can  be an IPv4 or IPv6 address string. As IPv6 addresses already
       contain colons, enclose host in a pair of square brackets when specify‐
       ing  an	IPv6 address string. Otherwise the first occurrence of a colon
       can be interpreted as the separator between the host name and path, for
       example, [1080::8:800:200C:417A]:tmp/file. See inet(7P) and inet6(7P).


	   Where  host is the name of the NFS server host, and pathname is the
	   path name of the directory on the server being  mounted.  The  path
	   name	 is  interpreted  according  to the server's path name parsing
	   rules and  is  not  necessarily  slash-separated,  though  on  most
	   servers, this is the case.


	   This is an NFS URL and follows the standard convention for NFS URLs
	   as described in NFS URL Scheme, RFC 2224.  See  the	discussion  of
	   URL's  and  the  public  option  under  NFS FILE SYSTEMS for a more
	   detailed discussion.

       host:pathname nfs://host[:port]/pathname

	   host:pathname is a comma-separated list of host:pathname.

	   See the discussion of replicated file systems  and  failover	 under
	   NFS FILE SYSTEMS for a more detailed discussion.

       hostlist pathname

	   hostlist is a comma-separated list of hosts.

	   See	the  discussion	 of replicated file systems and failover under
	   NFS FILE SYSTEMS for a more detailed discussion.

       The mount  command  maintains  a	 table	of  mounted  file  systems  in
       /etc/mnttab, described in mnttab(4).

       mount_nfs supports both NFSv3 and NFSv4 mounts. The default NFS version
       is NFSv4.

       See  mount(1M)  for  the	 list  of   supported	generic_options.   See
       share_nfs(1M) for a description of server options.

       -o specific_options

	   Set	file  system  specific	options according to a comma-separated
	   list with no intervening spaces.


	       Hold cached attributes for no more than n seconds after	direc‐
	       tory update.  The default value is 60.


	       Hold  cached  attributes for at least n seconds after directory
	       update. The default value is 30.


	       Hold cached attributes for no more than n  seconds  after  file
	       modification. The default value is 60.


	       Hold  cached attributes for at least n seconds after file modi‐
	       fication.  The default value is 3.


	       Set min and max times for regular files and  directories	 to  n
	       seconds. See "File Attributes," below, for a description of the
	       effect of setting this option to 0.

	       See "Specifying Values for Attribute Cache  Duration  Options,"
	       below,  for  a description of how acdirmax, acdirmin, acregmax,
	       acregmin, and actimeo are parsed on a mount command line.

	   bg | fg

	       If the first attempt fails, retry in the background, or, in the
	       foreground. The default is fg.

	   forcedirectio | noforcedirectio

	       If  forcedirectio  is  specified,  then for the duration of the
	       mount, forced direct I/O is used. If the filesystem is  mounted
	       using  forcedirectio,  data  is	transferred  directly  between
	       client and server, with no buffering  on	 the  client.  If  the
	       filesystem  is  mounted using noforcedirectio, data is buffered
	       on the client. forcedirectio is a performance option that is of
	       benefit	only  in large sequential data transfers.  The default
	       behavior is noforcedirectio.


	       By default, the GID associated with a newly created file	 obeys
	       the  System  V semantics; that is, the GID is set to the effec‐
	       tive GID of the calling process. This behavior can be  overrid‐
	       den  on a per-directory basis by setting the set-GID bit of the
	       parent directory; in this case, the GID of a newly created file
	       is  set	to  the	 GID  of the parent directory (see open(2) and
	       mkdir(2)). Files created on file systems that are mounted  with
	       the grpid option obeys BSD semantics independent of whether the
	       set-GID bit of the parent directory is set; that is, the GID is
	       unconditionally inherited from that of the parent directory.

	   hard | soft

	       Continue	 to retry requests until the server responds (hard) or
	       give up and return an error (soft). The default value is	 hard.
	       Note that NFSv4 clients do not support soft mounts.

	   intr | nointr

	       Allow (do not allow) keyboard interrupts to kill a process that
	       is hung while waiting for a response  on	 a  hard-mounted  file
	       system.	The  default  is  intr,	 which	makes  it possible for
	       clients to interrupt applications that can  be  waiting	for  a
	       remote mount.


	       Suppress	 data  and attribute caching. The data caching that is
	       suppressed is the write-behind. The local page cache  is	 still
	       maintained,  but	 data copied into it is immediately written to
	       the server.


	       Do not perform the normal  close-to-open	 consistency.  When  a
	       file  is	 closed, all modified data associated with the file is
	       flushed to the server and not held on the client. When  a  file
	       is  opened the client sends a request to the server to validate
	       the client's local caches. This behavior ensures a file's  con‐
	       sistency across multiple NFS clients. When -nocto is in effect,
	       the client does not perform the flush on close and the  request
	       for  validation,	 allowing  the possiblity of differences among
	       copies of the same file as stored on multiple clients.

	       This option can	be  used  where	 it  can  be  guaranteed  that
	       accesses	 to  a	specified  file	 system are made from only one
	       client and only that client. Under such a condition, the effect
	       of -nocto can be a slight performance gain.


	       The server IP port number. The default is NFS_PORT. If the port
	       option is specified, and if the resource includes one  or  more
	       NFS  URLs,  and	if any of the URLs include a port number, then
	       the port number in the option and in the URL must be the same.


	       Request POSIX.1 semantics for the file system. Requires a mount
	       Version 2 mountd(1M) on the server. See standards(5) for infor‐
	       mation regarding POSIX.

	   proto=netid | rdma

	       By default, the transport protocol that the NFS mount  uses  is
	       the first available RDMA transport supported both by the client
	       and the server. If no RDMA transport is found, then it attempts
	       to  use	a  TCP transport or, failing that, a UDP transport, as
	       ordered in the /etc/netconfig file. If it does not find a  con‐
	       nection oriented transport, it uses the first available connec‐
	       tionless transport.

	       Use this option to override the default behavior.

	       proto is set to the value of netid or rdma. netid is the	 value
	       of the network_id field entry in the /etc/netconfig file.

	       The  UDP	 protocol  is  not supported for NFS Version 4. If you
	       specify a UDP protocol with the proto option, NFS version 4  is
	       not used.


	       The public option forces the use of the public file handle when
	       connecting to the NFS server. The resource specified might  not
	       have  an	 NFS  URL.  See	 the discussion of URLs and the public
	       option under NFS FILE SYSTEMS for a more detailed discussion.

	   quota | noquota

	       Enable or prevent quota(1M) to check whether the user  is  over
	       quota  on  this	file  system;  if  the	file system has quotas
	       enabled on the server, quotas are still checked for  operations
	       on this file system.


	       Remounts	 a  read-only  file system as read-write (using the rw
	       option).	 This option cannot be used with other -o options, and
	       this option works only on currently mounted read-only file sys‐


	       Set the number of NFS retransmissions to n. The	default	 value
	       is  5.  For  connection-oriented transports, this option has no
	       effect because  it  is  assumed	that  the  transport  performs
	       retransmissions on behalf of NFS.


	       The  number  of times to retry the mount operation. The default
	       for the mount command is 10000.

	       The default for the automounter is 0, in other  words,  do  not
	       retry. You might find it useful to increase this value on heav‐
	       ily loaded servers, where automounter traffic is dropped, caus‐
	       ing unnecessary server not responding errors.


	       Set  the	 read buffer size to a maximum of n bytes. The default
	       value is 1048576 when  using  connection-orientated  transports
	       with Version 3 or Version 4 of the NFS protocol, and 32768 when
	       using connection-less transports. The default can be negotiated
	       down  if	 the  server  prefers  a smaller transfer size. "Read"
	       operations may not necessarily use  the	maximum	 buffer	 size.
	       When using Version 2, the default value is 32768 for all trans‐


	       Set the security mode for NFS  transactions.  If	 sec=  is  not
	       specified,  then the default action is to use AUTH_SYS over NFS
	       Version 2 mounts, use a user-configured default auth  over  NFS
	       version	3  mounts,  or	to   negotiate	a  mode over Version 4

	       The preferred mode for NFS Version 3 mounts is the default mode
	       specified  in  /etc/nfssec.conf	(see  nfssec.conf(4))  on  the
	       client. If there is no default configured in this  file	or  if
	       the  server  does  not  export using the client's default mode,
	       then the client picks the first mode that it  supports  in  the
	       array  of  modes returned by the server. These alternatives are
	       limited to the security flavors listed in /etc/nfssec.conf.

	       NFS Version 4 mounts negotiate a security mode when the	server
	       returns	an  array  of  security modes. The client attempts the
	       mount with each security mode, in order, until one is  success‐

	       Only  one  mode	can  be	 specified  with  the sec= option. See
	       nfssec(5) for the available mode options.


	       This option has been deprecated in favor of the sec=dh option.


	       Set the NFS timeout to n tenths of a second. The default	 value
	       is 11 tenths of a second for connectionless transports, and 600
	       tenths of a second  for	connection-oriented  transports.  This
	       value is ignored for connectionless transports. Such transports
	       might implement their own timeouts, which are outside the  con‐
	       trol of NFS.

	   vers=NFS version number

	       By default, the version of NFS protocol used between the client
	       and the server is the highest one available  on	both  systems.
	       The  default  maximum  for the client is Version 4. This can be
	       changed	by  setting  the   NFS_CLIENT_VERSMAX	parameter   in
	       /etc/default/nfs	 to  a	valid version (2, 3, or 4). If the NFS
	       server does not support the client's default maximum, the  next
	       lowest version attempted until a matching version is found.


	       Set  the write buffer size to a maximum of n bytes. The default
	       value is 1048576 when  using  connection-orientated  transports
	       with Version 3 or Version 4 of the NFS protocol, and 32768 when
	       using connection-less transports. The default can be negotiated
	       down  if	 the  server  prefers a smaller transfer size. "Write"
	       operations may not necessarily use  the	maximum	 buffer	 size.
	       When using Version 2, the default value is 32768 for all trans‐

	   xattr | noxattr

	       Allow or disallow the creation  and  manipulation  of  extended
	       attributes.  The default is xattr. See fsattr(5) for a descrip‐
	       tion of extended attributes.


	   Overlay mount. Allow the file system to be mounted over an existing
	   mount  point,  making the underlying file system inaccessible. If a
	   mount is attempted on a pre-existing mount  point  without  setting
	   this flag, the mount fails, producing the error "device busy."

       Background versus Foreground

	   File	 systems  mounted with the bg option indicate that mount is to
	   retry in the background if the server's mount  daemon  (mountd(1M))
	   does	 not respond. mount retries the request up to the count speci‐
	   fied in the retry=n option. (Note that the default value for	 retry
	   differs  between mount and automount. See the description of retry,
	   above.) Once the file system is mounted, each NFS request  made  in
	   the	kernel waits timeo=n tenths of a second for a response.	 If no
	   response arrives, the time-out is multiplied by 2 and  the  request
	   is  retransmitted.  When  the number of retransmissions has reached
	   the number specified in the retrans=n option, a file system mounted
	   with	 the  soft option returns an error on the request; one mounted
	   with the hard option prints a  warning  message  and	 continues  to
	   retry the request.

       Hard versus Soft

	   File systems that are mounted read-write or that contain executable
	   files should always be mounted with the hard	 option.  Applications
	   using  soft	mounted	 file systems can incur unexpected I/O errors,
	   file corruption, and unexpected program core dumps. The soft option
	   is not recommended.

       Authenticated requests

	   The	server can require authenticated NFS requests from the client.
	   sec=dh authentication might be required. See nfssec(5).

       URLs and the public option

	   If the public option is specified, or if the resource includes  and
	   NFS	URL,  mount attempts to connect to the server using the public
	   file handle lookup protocol. See WebNFS Client  Specification,  RFC
	   2054. If the server supports the public file handle, the attempt is
	   successful; mount does not need to contact the server's rpcbind(1M)
	   and	the  mountd(1M)	 daemons  to  get the port number of the mount
	   server and the initial file handle of  pathname,  respectively.  If
	   the	NFS  client and server are separated by a firewall that allows
	   all outbound connections through specific ports, such as  NFS_PORT,
	   then	 this  enables NFS operations through the firewall. The public
	   option and the NFS URL can be specified independently or  together.
	   They interact as specified in the following matrix:

				Resource Style

				 host:pathname		    NFS URL

	     public option	Force public file	   Force public file
				 handle and fail	    handle and fail
				 mount if not supported.    mount if not supported.

				 Use Native paths.	    Use Canonical paths.

	     default		Use MOUNT protocol.	   Try public file handle
							    with Canonical paths.
							    Fall back to MOUNT
							    protocol if not

	   A  Native path is a path name that is interpreted according to con‐
	   ventions used on the native operating system of the NFS  server.  A
	   Canonical  path is a path name that is interpreted according to the
	   URL rules. See Uniform Resource Locators (URL), RFC 1738. See   for
	   uses of Native and Canonical paths.

       Replicated file systems and failover

	   resource  can  list	multiple  read−only file systems to be used to
	   provide data. These file systems should contain  equivalent	direc‐
	   tory	 structures  and  identical files. It is also recommended that
	   they be created by a utility such as rdist(1). The file systems can
	   be  specified  either with a comma−separated list of host:/pathname
	   entries and/or NFS URL entries, or with a comma −separated list  of
	   hosts, if all file system names are the same. If multiple file sys‐
	   tems are named and the first server in the list is  down,  failover
	   uses	 the  next  alternate server to access files. If the read−only
	   option is not chosen, replication is disabled. File access, for NFS
	   Versions  2	and  3,	 is  blocked  on the original if NFS locks are
	   active for that file.

   File Attributes
       To improve NFS read performance, files and file attributes are  cached.
       File  modification  times get updated whenever a write occurs. However,
       file access times can be temporarily out-of-date until the  cache  gets

       The  attribute  cache retains file attributes on the client. Attributes
       for a file are assigned a time to be flushed. If the file  is  modified
       before  the  flush  time,  then	the flush time is extended by the time
       since the last modification  (under  the	 assumption  that  files  that
       changed	recently  are  likely  to change soon). There is a minimum and
       maximum flush time extension for regular	 files	and  for  directories.
       Setting	actimeo=n  sets flush time to n seconds for both regular files
       and directories.

       Setting actimeo=0 disables attribute caching on the client. This	 means
       that  every  reference  to  attributes  is  satisfied directly from the
       server though file data is still cached. While this guarantees that the
       client always has the latest file attributes from the server, it has an
       adverse effect on performance through additional latency, network load,
       and server load.

       Setting	the  noac  option also disables attribute caching, but has the
       further effect of disabling client write caching. While this guarantees
       that  data  written  by an application is written directly to a server,
       where it can be viewed immediately by other clients, it has a  signifi‐
       cant adverse effect on client write performance. Data written into mem‐
       ory-mapped file pages  (mmap(2))	 are  not  written  directly  to  this

   Specifying Values for Attribute Cache Duration Options
       The  attribute cache duration options are acdirmax, acdirmin, acregmax,
       acregmin, and actimeo, as described under OPTIONS.  A  value  specified
       for  actimeo  sets  the	values of all attribute cache duration options
       except for any of these options specified following actimeo on a	 mount
       command line. For example, consider the following command:

	 example# mount -o acdirmax=10,actimeo=1000 server:/path /localpath

       Because	actimeo	 is  the last duration option in the command line, its
       value (1000) becomes the setting	 for  all  of  the  duration  options,
       including acdirmax. Now consider:

	 example# mount -o actimeo=1000,acdirmax=10 server:/path /localpath

       Because	the acdirmax option follows actimeo on the command line, it is
       assigned the value specified (10). The remaining duration  options  are
       set to the value of actimeo (1000).

       Example 1 Mounting an NFS File System

       To mount an NFS file system:

	 example# mount serv:/usr/src /usr/src

       Example 2 Mounting An NFS File System Read-Only With No suid Privileges

       To mount an NFS file system read-only with no suid privileges:

	 example# mount -r -o nosuid serv:/usr/src /usr/src

       Example	3  Mounting  An	 NFS  File System Over Version 2, with the UDP

       To mount an NFS file system over Version 2, with the UDP transport:

	 example# mount -o vers=2,proto=udp serv:/usr/src /usr/src

       Example 4 Mounting an NFS File System Using An NFS URL

       To mount an NFS file system using an NFS URL (a canonical path):

	 example# mount nfs://serv/usr/man /usr/man

       Example 5 Mounting An NFS File System Forcing Use Of  The  Public  File

       To mount an NFS file system and force the use of the public file handle
       and an NFS URL (a canonical path) that has a  non  7-bit	 ASCII	escape

	 example# mount -o public nfs://serv/usr/%A0abc /mnt/test

       Example 6 Mounting an NFS File System Using a Native Path

       To  mount an NFS file system using a native path (where the server uses
       colons (":") as the component separator) and the public file handle:

	 example# mount -o public serv:C:doc:new /usr/doc

       Example 7 Mounting a Replicated Set of NFS File Systems with  the  Same

       To mount a replicated set of NFS file systems with the same pathnames:

	 example# mount serv−a,serv−b,serv−c:/usr/man /usr/man

       Example	8 Mounting a Replicated Set of NFS File Systems with Different

       To mount a replicated set of NFS file systems with different pathnames:

	 example# mount serv−x:/usr/man,serv−y:/var/man,nfs://serv-z/man /usr/man


	   table of mounted file systems


	   default distributed file system type


	   table of automatically mounted resources

       rdist(1), lockd(1M),  mountall(1M),  mountd(1M),	 nfsd(1M),  quota(1M),
       statd(1M),  mkdir(2), mmap(2), mount(2), open(2), umount(2), mnttab(4),
       nfs(4),	nfssec.conf(4),	 attributes(5),	 fsattr(5),  nfssec(5),	 stan‐
       dards(5), inet(7P), inet6(7P), lofs(7FS)

       Callaghan, Brent, WebNFS Client Specification, RFC 2054, October 1996.

       Callaghan, Brent, NFS URL Scheme, RFC 2224, October 1997.

       Berners-Lee, Masinter & McCahill , Uniform Resource Locators (URL), RFC
       1738, December 1994.

       An NFS server should not attempt to mount its  own  file	 systems.  See

       If  the directory on which a file system is to be mounted is a symbolic
       link, the file system is mounted on the directory to which the symbolic
       link  refers,  rather  than  being  mounted on top of the symbolic link

       SunOS 4.x used the biod maintenance procedure to perform parallel read-
       ahead  and  write-behind	 on  NFS clients. SunOS 5.x made biod obsolete
       with multi-threaded processing, which transparently  performs  parallel
       read-ahead and write-behind.

       Since  the root (/) file system is mounted read-only by the kernel dur‐
       ing the boot process, only the remount option (and options that can  be
       used  in	 conjunction  with  remount)  affect the root (/) entry in the
       /etc/vfstab file.

       mount_cachefs cannot be used with replicated NFS mounts or any NFS Ver‐
       sion 4 mount.

       The  NFS	 client service is managed by the service management facility,
       smf(5), under the service identifier:


       Administrative actions on this service, such as enabling, disabling, or
       requesting  restart,  can  be performed using svcadm(1M). The service's
       status can be queried using the svcs(1) command.

				 Jul 26, 2009			 MOUNT_NFS(1M)

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