# exportd

## NAME



           nfsv4.exportd - NFSv4 Server Mount Daemon
    


## SYNOPSIS



           **/usr/sbin/nfsv4.exportd [**_options_**]**
    


## DESCRIPTION



           The **nfsv4.exportd** is used to manage NFSv4 exports.  The NFS server
           (_nfsd_) maintains a cache of authentication and authorization
           information which is used to identify the source of each request,
           and then what access permissions that source has to any local
           filesystem.  When required information is not found in the cache,
           the server sends a request to **nfsv4.exportd** to fill in the missing
           information.  **nfsv4.exportd** uses a table of information stored in
           **/var/lib/nfs/etab** and maintained by exportfs(8), possibly based on
           the contents of exports(5), to respond to each request.
    


## OPTIONS



           **-d kind  or  --debug kind**
                  Turn on debugging. Valid kinds are: all, auth, call,
                  general and parse.
    
           **-l** or **--log-auth**
                  Enable logging of responses to authentication and access
                  requests from nfsd.  Each response is then cached by the
                  kernel for 30 minutes (or as set by **--ttl** below), and will
                  be refreshed after 15 minutes (half the ttl time) if the
                  relevant client remains active.  Note that **-l** is equivalent
                  to **-d auth** and so can be enabled in **/etc/nfs.conf** with
                  **"debug = auth"** in the **[exportd]** section.
    
           **-i** or **--cache-use-ipaddr**
                  Normally each client IP address is matched against each
                  host identifier (name, wildcard, netgroup etc) found in
                  **/etc/exports** and a combined identity is formed from all
                  matching identifiers.  Often many clients will map to the
                  same combined identity so performing this mapping reduces
                  the number of distinct access details that the kernel needs
                  to store.  Specifying the **-i** option suppresses this mapping
                  so that access to each filesystem is requested and cached
                  separately for each client IP address.  Doing this can
                  increase the burden of updating the cache slightly, but can
                  make the log messages produced by the **-l** option easier to
                  read.
    
           **-T  or  --ttl**
                  Provide a time-to-live (TTL) for cached information given
                  to the kernel.  The kernel will normally request an update
                  if the information is needed after half of this time has
                  expired.  Increasing the provided number, which is in
                  seconds, reduces the rate of cache update requests, and
                  this is particularly noticeable when these requests are
                  logged with **-l**.  However increasing also means that changes
                  to hostname to address mappings can take longer to be
                  noticed.  The default TTL is 1800 (30 minutes).
    
           **-F  or  --foreground**
                  Run in foreground (do not daemonize)
    
           **-h  or  --help**
                  Display usage message.
    
           **-t N** or **--num-threads=N** or **--num-threads N**
                  This option specifies the number of worker threads that
                  **nfsv4.exports** spawns.  The default is 1 thread, which is
                  probably enough.  More threads are usually only needed for
                  NFS servers which need to handle mount storms of hundreds
                  of NFS mounts in a few seconds, or when your DNS server is
                  slow or unreliable.
    
           **-g** or **--manage-gids**
                  Accept requests from the kernel to map user id numbers into
                  lists of group id numbers for use in access control.  An
                  NFS request will normally (except when using Kerberos or
                  other cryptographic authentication) contain a user-id and a
                  list of group-ids.  Due to a limitation in the NFS
                  protocol, at most 16 groups ids can be listed.  If you use
                  the **-g** flag, then the list of group ids received from the
                  client will be replaced by a list of group ids determined
                  by an appropriate lookup on the server. Note that the
                  'primary' group id is not affected so a **newgroup** command on
                  the client will still be effective.  This function requires
                  a Linux Kernel with version at least 2.6.21.
    


## CONFIGURATION FILE



           Many of the options that can be set on the command line can also
           be controlled through values set in the **[exportd]** or, in some
           cases, the **[nfsd]** sections of the _/etc/nfs.conf_ configuration
           file.  Values recognized in the **[exportd]** section include
           **cache-use-ipaddr , ttl** , **manage-gids** , and **debug** which each have the
           same effect as the option with the same name.
    


## FILES



           _/etc/exports_
                  input file for **exportfs** , listing exports, export options,
                  and access control lists
    


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