+to be used in a High Availability NFS (HA-NFS) environment.
+.IP
+The callout program is run with 4 arguments.
+The first is
+.B mount
+or
+.B unmount
+depending on the reason for the callout.
+The second will be the name of the client performing the mount.
+The third will be the path that the client is mounting.
+The last is the number of concurrent mounts that we believe the client
+has of that path.
+.IP
+This callout is not needed with 2.6 and later kernels.
+Instead, mount the nfsd filesystem on
+.IR /proc/fs/nfsd .
+.TP
+.BI "\-s," "" " \-\-state\-directory\-path " directory
+Specify a directory in which to place statd state information.
+If this option is not specified the default of
+.I /var/lib/nfs
+is used.
+.TP
+.BI "\-r," "" " \-\-reverse\-lookup"
+.B rpc.mountd
+tracks IP addresses in the
+.I rmtab
+file. When a DUMP request is made (by
+someone running
+.BR "showmount -a" ,
+for instance), it returns IP addresses instead
+of hostnames by default. This option causes
+.B rpc.mountd
+to perform a reverse lookup on each IP address and return that hostname instead.
+Enabling this can have a substantial negative effect on performance
+in some situations.
+.TP
+.BR "\-t N" " or " "\-\-num\-threads=N"
+This option specifies the number of worker threads that rpc.mountd
+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.