ORTE_SNAPC(7)							     Open MPI							     ORTE_SNAPC(7)

NAME

       ORTE_SNAPC  - Open RTE MCA Snapshot Coordination (SnapC) Framework: Overview of Open RTE's SnapC framework, and selected modules.  Open MPI
       1.4.5

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.

       snapc_base_global_snapshot_dir
	   The directory to store the checkpoint snapshots. Default is /tmp.

   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)

1.4.5								   Feb 10, 2012 						     ORTE_SNAPC(7)