+.B \-H " or " \-\-ha-callout prog
+Specify a high availability callout program, which will receive callouts
+for all client mount and unmount requests. This allows
+.B rpc.mountd
+to be used in a High Availability NFS (HA-NFS) environment. This callout is not
+needed (and should not be used) with 2.6 and later kernels (instead,
+mount the nfsd filesystem on
+.B /proc/fs/nfsd
+).
+The program will be called with 4 arguments.
+The first will be
+.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.
+.TP
+.BI "\-P," "" " \-\-state\-directory\-path " directory
+specify a directory in which to place statd state information.
+If this option is not specified the default of
+.BR /var/lib/nfs
+is used.
+.TP
+.BI "\-r," "" " \-\-reverse\-lookup"
+mountd tracks IP addresses in the rmtab, and when a DUMP request is made (by
+someone running showmount -a, for instance), it returns IP addresses instead
+of hostnames by default. This option causes mountd to do 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.
+.TP