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 invocation.  At a minimum,  the  node  ID
       and the associated host name is given on the command line.
       Once lamshrink completes, the node ID  is  invalid  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  default,
       SIGFUSE  is ignored.  A different handler can be installed
       with ksignal(2).

       All application processes on all remaining nodes  are  al­
       ways  informed  of the death of a node.  This is also done
       with a signal (SIGSHRINK), which by default causes a  pro­
       cess'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  han­
       dler.   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

       ticular, 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 silent­
           ly.


SEE ALSO

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


Man(1) output converted with man2html