sm-notify(8)						      System Manager's Manual						      sm-notify(8)

NAME

       sm-notify - Send out NSM reboot notifications

SYNOPSIS

       /sbin/sm-notify [-dfq] [-m time] [-p port] [-P path] [-v my_name ]

DESCRIPTION

       File locking over NFS (v2 and v3) requires a facility to notify peers in case of a reboot, so that clients can reclaim locks after a server
       crash, and/or servers can release locks held by the rebooted client.

       This is a two-step process: during normal operations, a mechanism is required to keep track of which hosts need to be informed of a reboot.
       And of course, notifications need to be sent out during reboot.	The protocol used for this is called NSM, for Network Status Monitor.

       This  implementation  separates	these into separate program.  rpc.statd tracks hosts which need to be notified and this sm-notify performs
       the notification.  When rpc.statd is started it will typically started sm-notify but this is configurable.

   Operation
       For each NFS client or server machine to be monitored, rpc.statd creates a file in /var/lib/nfs/sm, and removes the file if  monitoring	is
       no longer required.

       When the machine is rebooted, sm-notify iterates through these files and notifies the peer statd server on those machines.

       Each  machine  has  an NSM state , which is basically an integer counter that is incremented each time the machine reboots. This counter is
       stored in /var/lib/nfs/state, and updated by sm-notify.

   Security
       sm-notify has little need for root privileges and so drops them as soon as possible.  It continues to need to make changes to  the  sm  and
       sm.bak  directories so to be able to drop privileges, these must be writable by a non-privileged user.  If these directories are owned by a
       non-root user, sm-notify will drop privilege to match that user once it has created sockets for sending out request  (for  which  it  needs
       privileged) but before it processes any reply (which is the most likely source of possible privilege abuse).

OPTIONS

       -m failtime
	      When  notifying  hosts,  sm-notify will try to contact each host for up to 15 minutes, and will give up if unable to reach it within
	      this time frame.

	      Using the -m option, you can override this. A value of 0 tells sm-notify to retry indefinitely; any other value  is  interpreted	as
	      the maximum retry time in minutes.

       -v ipaddr-or-hostname
	      This  option tells sm-notify to bind to the specified ipaddr, (or the ipaddr of the given hostname) so that all notification packets
	      originate from this address.  This is useful for NFS failover.  The given name is also used as the name of  this	host  in  the  NSM
	      request.

       -p port
	      instructs  sm-notify  to bind to the indicated IP port number. If this option is not given, it will try to bind to a randomly chosen
	      privileged port below 1024.

       -q     Be quiet. This suppresses all messages except error messages while collecting the list of hosts.

       -P /path/to/state/directory
	      If sm-notify should look in a no-standard place of state file, the path can be given here.  The directories sm and  sm.bak  and  the
	      file state must exist in that directory with the standard names.

       -f     If  the  state  path has not been reset with -P, sm-notify will normally create a file in /var/run to indicate that it has been run.
	      If this file is found when sm-notify starts, it will not run again (as it is normally only needed once  per  reboot).   If  -f  (for
	      force) is given, sm-notify will run even if the file in /var/run is present.

       -n     Do not update the NSM state. This is for testing only.  Setting this flag implies -f.

       -d     Enables  debugging.   By	default,  sm-notify  forks  and  puts  itself  in  the	background  after obtaining the list of hosts from
	      /var/lib/nfs/sm.

FILES

       /var/lib/nfs/state
       /var/lib/nfs/sm/*
       /var/lib/nfs/sm.bak/*
       /var/run/sm-notify.pid

SEE ALSO

       rpc.nfsd(8), portmap(8)

AUTHORS

       Olaf Kirch <okir@suse.de>

								    19 Mar 2007 						      sm-notify(8)