LAMSHRINK(1)							   LAM COMMANDS 						      LAMSHRINK(1)

NAME

       lamshrink - Shrink a LAM multicomputer.

SYNTAX

       lamshrink [-hv] [-w <delay>] [-u <userid>] <node> <hostname>

OPTIONS

       -h	     Print useful information on this command.

       -v	     Be verbose.

       <hostname>    Remove the LAM node on this host.

       <node>	     Remove the LAM node with this ID.

       -w <delay>    Notify processes on the doomed node and pause for <delay> seconds before proceeding.

       -u <userid>   Use this userid to access the host.

DESCRIPTION

       An existing LAM session, initiated by lamboot(1), can be shrunk to include less nodes with lamshrink.  One node is removed for each invoca-
       tion.  At a minimum, the node ID and the associated host name is given on the command line.  Once lamshrink completes, the node ID  is  in-
       valid across the remaining nodes.  If a different userid is required to access the host, it is specified with the -u option.

       Existing  application  processes on the target node can be warned of impending shutdown with the -w option.  A LAM signal (SIGFUSE) will be
       sent to these processes and lamshrink will then pause for the given number of seconds before proceeding with removing  the  node.   By  de-
       fault, SIGFUSE is ignored.  A different handler can be installed with ksignal(2).

       All  application processes on all remaining nodes are always informed of the death of a node.  This is also done with a signal (SIGSHRINK),
       which by default causes a process's runtime route cache to be flushed (to remove any cached information on the dead node).  If this  signal
       is  re-vectored	for the purpose of fault tolerance, the old handler should be called at the beginning of the new handler.  The signal does
       not, by itself, give the process information on which node has been removed.  One technique for getting this information is  to	query  the
       router for information on all relevant nodes using getroute(2).	The dead node will cause this routine to return an error.

   FAULT TOLERANCE
       If enabled with lamboot(1), LAM will watch for nodes that fail.	The procedure for removing a node that has failed is the same as lamshrink
       after the warning step.	In particular, the SIGSHRINK signal is delivered.

EXAMPLES

       lamshrink -v newhost n1
	   Remove LAM on newhost, known within LAM as node 1.  Report about important steps as they are done.

       lamshrink newhost n30 -w 10
	   Inform all processes on LAM node 30, which is running on newhost, that the node will be dead in 10 seconds.	Wait 10 seconds and remove
	   the node.  Operate silently.

SEE ALSO

       lamboot(1), tkill(1), ksignal(2), getroute(2)

LAM 6.5.8							  November, 2002						      LAMSHRINK(1)