    NAME
         checkpoint - Sun Grid Engine checkpointing environment  con-
         figuration file format

    DESCRIPTION
         Checkpointing is a facility to save the complete  status  of
         an  executing program or job and to restore and restart from
         this so called checkpoint at a later point of  time  if  the
         original  program  or job was halted, e.g.  through a system
         crash.

         Sun Grid Engine provides  various  levels  of  checkpointing
         support  (see  sge_ckpt(1)).   The checkpointing environment
         described here is a means to configure the  different  types
         of  checkpointing in use for your Sun Grid Engine cluster or
         parts thereof. For that purpose you can  define  the  opera-
         tions  which  have to be executed in initiating a checkpoint
         generation, a migration of a checkpoint to another host or a
         restart of a checkpointed application as well as the list of
         queues which are eligible for a checkpointing method.

         Supporting different operating systems may easily force  Sun
         Grid  Engine  to introduce operating system dependencies for
         the configuration of the  checkpointing  configuration  file
         and  updates  of the supported operating system versions may
         lead to frequently changing implementation  details.  Please
         refer to the <sge_root>/ckpt directory for more information.

         Please use the -ackpt, -dckpt, -mckpt or -sckpt  options  to
         the  qconf(1)  command  to manipulate checkpointing environ-
         ments from the command-line or use the corresponding qmon(1)
         dialogue for X-Windows based interactive configuration.

         Note, Sun Grid Engine allows  backslashes  (\)  be  used  to
         escape  newline (\newline) characters. The backslash and the
         newline are replaced with a space (" ") character before any
         interpretation.

    FORMAT
         The format of a checkpoint file is defined as follows:

      ckpt_name
         The name of the checkpointing  environment  as  defined  for
         ckpt_name  in sge_types(1).  qsub(1) -ckpt switch or for the
         qconf(1) options mentioned above.

      interface
         The type of checkpointing to be used. Currently, the follow-
         ing types are valid:

         hibernator
              The   Hibernator   kernel   level   checkpointing    is
              interfaced.

         cpr  The SGI kernel level checkpointing is used.

         cray-ckpt
              The Cray kernel level checkpointing is assumed.

         transparent
              Sun Grid Engine assumes that the  jobs  submitted  with
              reference  to this checkpointing interface use a check-
              pointing library such as provided by the public  domain
              package Condor.

         userdefined
              Sun Grid Engine assumes that the  jobs  submitted  with
              reference to this checkpointing interface perform their
              private checkpointing method.

         application-level
              Uses all of the interface commands  configured  in  the
              checkpointing  object  like  in  the case of one of the
              kernel level checkpointing interfaces (cpr,  cray-ckpt,
              etc.) except for the restart_command (see below), which
              is not used (even if it  is  configured)  but  the  job
              script is invoked in case of a restart instead.

      ckpt_command
         A command-line type command string to  be  executed  by  Sun
         Grid Engine in order to initiate a checkpoint.

      migr_command
         A command-line type command string to  be  executed  by  Sun
         Grid  Engine  during a migration of a checkpointing job from
         one host to another.

      restart_command
         A command-line type command string to  be  executed  by  Sun
         Grid Engine when restarting a previously checkpointed appli-
         cation.

      clean_command
         A command-line type command string to  be  executed  by  Sun
         Grid  Engine in order to cleanup after a checkpointed appli-
         cation has finished.

      ckpt_dir
         A file system location to which checkpoints  of  potentially
         considerable size should be stored.

      ckpt_signal
         A Unix signal to be sent to a job by Sun Grid Engine to ini-
         tiate  a checkpoint generation. The value for this field can
         either be a symbolic name from the list produced by  the  -l
         option  of  the  kill(1)  command or an integer number which
         must be a valid signal on the systems used  for  checkpoint-
         ing.

      when
         The points of time when checkpoints are expected to be  gen-
         erated.  Valid values for this parameter are composed by the
         letters s, m, x and r and any combinations  thereof  without
         any  separating  character  in between. The same letters are
         allowed for the -c option of the qsub(1) command which  will
         overwrite the definitions in the used checkpointing environ-
         ment.  The meaning of the letters is defined as follows:

         s    A job is checkpointed, aborted and if possible migrated
              if  the  corresponding sge_execd(8) is shut down on the
              job's machine.

         m    Checkpoints   are   generated   periodically   at   the
              min_cpu_interval  interval  defined  by  the queue (see
              queue_conf(5)) in which a job executes.

         x    A job is checkpointed, aborted and if possible migrated
              as  soon as the job gets suspended (manually as well as
              automatically).

         r    A job will be rescheduled (not checkpointed)  when  the
              host  on which the job currently runs went into unknown
              state and the  time  interval  reschedule_unknown  (see
              sge_conf(5)) defined in the global/local cluster confi-
              guration will be exceeded.

    RESTRICTIONS
         Note, that the functionality of any checkpointing, migration
         or  restart procedures provided by default with the Sun Grid
         Engine distribution as well as the way how they are  invoked
         in the ckpt_command, migr_command or restart_command parame-
         ters of any default checkpointing environments should not be
         changed  or  otherwise  the  functionality  remains the full
         responsibility of the administrator configuring  the  check-
         pointing  environment.   Sun  Grid  Engine  will just invoke
         these procedures and evaluate their exit status. If the pro-
         cedures  do  not  perform  their  tasks  properly or are not
         invoked in a proper fashion, the checkpointing mechanism may
         behave  unexpectedly, Sun Grid Engine has no means to detect
         this.

    SEE ALSO
         sge_intro(1), sge_ckpt(1), sge__types(1), qconf(1), qmod(1),
         qsub(1), sge_execd(8).

    COPYRIGHT
         See sge_intro(1) for a full statement of rights and  permis-
         sions.