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exportfs(8)									      exportfs(8)

       exportfs - maintain list of NFS exported file systems

       /usr/sbin/exportfs [-avi] [-o options,..] [client:/path ..]
       /usr/sbin/exportfs -r [-v]
       /usr/sbin/exportfs [-av] -u [client:/path ..]
       /usr/sbin/exportfs [-v]

       The  exportfs  command  is used to maintain the current table of exported file systems for
       NFS. This list is kept in a separate file named /var/lib/nfs/xtab which is read by  mountd
       when  a	remote host requests access to mount a file tree, and parts of the list which are
       active are kept in the kernel's export table.

       Normally this xtab file is initialized  with  the  list	of  all  file  systems	named  in
       /etc/exports by invoking exportfs -a.

       However, administrators can choose to add and delete individual file systems without modi-
       fying /etc/exports using exportfs.

       Any export requests which identify a specific host (rather than a subnet or netgroup  etc)
       are  entered  directly  into  the  kernel's  export  table  as  well  as  being written to
       /var/lib/nfs/xtab.  Further, any mount points listed in /var/lib/nfs/rmtab which  match	a
       non host-specific export request will cause an appropriate export entry for the host given
       in rmtab to be entered into the kernel's export table.

       -a     Export or unexport all directories.

       -o options,...
	      Specify a list of export options in the same manner as in exports(5).

       -i     Ignore the /etc/exports file, so that only default options and options given on the
	      command line are used.

       -r     Reexport	all  directories. It synchronizes /var/lib/nfs/xtab with /etc/exports. It
	      removes entries in /var/lib/nfs/xtab  which  are	deleted  from  /etc/exports,  and
	      remove any entries from the kernel export table which are no longer valid.

       -u     Unexport one or more directories.

       -v     Be  verbose.  When exporting or unexporting, show what's going on. When dis-
	      playing the current export list, also display the list of export options.

   Exporting Directories
       The first synopsis shows how to invoke the command when adding new entries  to  the
       export  table.	When using exportfs -a, all directories in exports(5) are added to
       xtab and the resulting list is pushed into the kernel.

       The host:/path argument specifies the directory to export along with  the  host	or
       hosts to export it to. All formats described in exports(5) are supported; to export
       a directory to the world, simply specify :/path.

       The export options  for	a  particular  host/directory  pair  derive  from  several
       sources.   There  is a set of default options which can be overridden by entries in
       /etc/exports (unless the -i option is given).  In addition, the	administrator  may
       overide	any  options from these sources using the -o argument which takes a comma-
       separated list of options in  the  same	fashion  as  one  would  specify  them	in
       exports(5).   Thus,  exportfs  can  also be used to modify the export options of an
       already exported directory.

       Modifications of the kernel export table used by  nfsd(8)  take	place  immediately
       after parsing the command line and updating the xtab file.

       The default export options are sync,ro,root_squash,no_delay.

   Unexporting Directories
       The  third  synopsis  shows how to unexported a currently exported directory.  When
       using exportfs -ua, all entries listed in xtab are removed from the  kernel  export
       tables, and the file is cleared. This effectively shuts down all NFS activity.

       To  remove  individial  export  entries,  one  can  specify a host:/path pair. This
       deletes the specified entry from xtab and removes the  corresponding  kernel  entry
       (if any).

   Dumping the Export Table
       Invoking  exportfs  without further options shows the current list of exported file
       systems.  When giving the -v option, the list of flags pertaining  to  each  export
       are shown in addition.

       The  following adds all directories listed in /etc/exports to /var/lib/nfs/xtab and
       pushes the resulting export entries into the kernel:

       # exportfs -a

       To export the /usr/tmp directory to host djando, allowing asynchronous writes,  one
       would do this:

       # exportfs -o async django:/usr/tmp

       Exporting  to  IP  networks, DNS and NIS domains does not enable clients from these
       groups to access NFS immediately; rather, these	sorts  of  exports  are  hints	to
       mountd(8)  to  grant  any mount requests from these clients.  This is usually not a
       big problem, because any existing mounts are preserved in rmtab across reboots.

       When unexporting a network or domain entry, any current exports to members of  this
       group  will  be	checked against the remaining valid exports and if they themselves
       are nolonger valid they will be removed.

       exports(5), mountd(8)

       Olaf Kirch, <okir@monad.swb.de>
       Neil Brown, <neilb@cse.unsw.edu.au>

					    7 Sep 1999				      exportfs(8)
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