1LAMHALT(1)                         LAM TOOLS                        LAMHALT(1)
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NAME

6       lamhalt - Shutdown the LAM/MPI run-time environment.
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SYNTAX

9       lamhalt [-dhHv]
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OPTIONS

12       -d          Turn on debugging mode.  This implies -v.
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14       -h          Print the command help menu.
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16       -i          Return  immediately  (even before the LAM universe is fully
17                   halted); deprecated
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19       -H          Suppress printing the header message.
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21       -v          Be verbose.
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DESCRIPTION

24       The lamhalt tool terminates the LAM software on each of the nodes  that
25       were  initially booted with lamboot and/or lamgrow.  No additional com‐
26       mand line arguments are necessary - lamhalt simply sends a  message  to
27       each  remote  node  telling  it to shut down.  Each remote node invokes
28       tkill(1) locally to shut down.  See tkill(1) for a description  of  how
29       LAM is terminated on each node.
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31       lamhalt  may  fail  if one of the remote nodes has failed, and does not
32       respond to lamhalt's queries.  In this  case,  the  lamwipe(1)  command
33       should be used to shut down LAM/MPI.  If lamwipe(1) fails, the user can
34       manually invoke tkill(1) on the troubled node.  In extreme  cases,  the
35       user may have to terminate individual LAM processes with kill(1).
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37       Older  versions  of  lamhalt would return 1-3 seconds before the entire
38       LAM universe was shut down.  This caused problems for some  LAM  users,
39       particularly  those  who  had  scripts that invoked lamboot immediately
40       after lamhalt.  lamhalt has therefore been changed to  wait  until  the
41       entire  LAM  universe is down before exiting.  This makes the execution
42       of lamhalt take a few seconds (typically less than 5).
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44       For users who want the old lamhalt behavior, use the  -i  (or  "immedi‐
45       ate")  switch,  which  will cause lamhalt to return immediately, likely
46       before the entire LAM universe has been taken down.
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EXAMPLES

49       lamhalt -d
50           Shutdown LAM on the machines and be verbose about its actions.
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SEE ALSO

53       recon(1), lamboot(1), tkill(1), bhost(5), lam-helpfile(5), lamwipe(1)
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57LAM 7.1.2                         March, 2006                       LAMHALT(1)