ORTE_SNAPC(7)                      Open MPI                      ORTE_SNAPC(7)



NAME
       Open RTE MCA Snapshot Coordination (SnapC) Framework - Overview of Open
       RTE's SnapC framework, and selected modules.  Open MPI 1.4.1

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)



1.4.1                            Jan 14, 2010                    ORTE_SNAPC(7)
