NAME

       ORTE_SNAPC  -  Open  RTE  MCA  Snapshot  Coordination  (SnapC)  Framework:  Overview  of Open RTE's SnapC
       framework, and selected modules.  Open MPI 4.1.6

DESCRIPTION

       Open RTE can coordinate the generation of a global snapshot of a parallel job from many distributed local
       snapshots.  The  components  in  this framework determine how to: Initiate the checkpoint of the parallel
       application, gather together the many distributed local snapshots, and provide the  user  with  a  global
       snapshot handle reference that can be used to restart the parallel application.

GENERAL PROCESS REQUIREMENTS

       In  order  for  a  process  to  use  the  Open  RTE SnapC components it must adhear to a few programmatic
       requirements.

       First, the program must call ORTE_INIT early in its execution. This should only be called once, and it is
       not possible to checkpoint the process without it first having called this function.

       The program must call ORTE_FINALIZE before termination.

       A  user  may  initiate  a  checkpoint of a parallel application by using the orte-checkpoint(1) and orte-
       restart(1) commands.

AVAILABLE COMPONENTS

       Open RTE ships with one SnapC component: full.

       The following MCA parameters apply to all components:

       snapc_base_verbose
           Set the verbosity level for all components. Default is 0, or silent except on error.

   full SnapC Component
       The full component gathers together the local snapshots to the disk local to the Head Node Process  (HNP)
       before  completing  the  checkpoint  of the process. This component does not currently support replicated
       HNPs, or timer based gathering of local snapshot data. This is a 3-tiered hierarchy of coordinators.

       The full component has the following MCA parameters:

       snapc_full_priority
           The component's priority to use when selecting the most appropriate component for a run.

       snapc_full_verbose
           Set the verbosity level for this component. Default is 0, or silent except on error.

   none SnapC Component
       The none component simply selects no SnapC component. All of the SnapC function calls return  immediately
       with ORTE_SUCCESS.

       This  component  is the last component to be selected by default. This means that if another component is
       available, and the none component was not explicity requested then ORTE will attempt to activate  all  of
       the available components before falling back to this component.

SEE ALSO

         orte-checkpoint(1), orte-restart(1), opal-checkpoint(1), opal-restart(1), orte_filem(7), opal_crs(7)