CHECKPOINT(5)						   Sun Grid Engine File Formats 					     CHECKPOINT(5)

NAME

       checkpoint - Sun Grid Engine checkpointing environment configuration 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 operations 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 environments 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 (
ewline) 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).  To be used in the qsub(1) -ckpt switch or for the
       qconf(1) options mentioned above.

   interface
       The type of checkpointing to be used. Currently, the following 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 checkpointing 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 application.

   clean_command
       A command-line type command string to be executed by Sun Grid Engine in order to cleanup after a checkpointed application 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 initiate 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 checkpointing.

   when
       The points of time when checkpoints are expected to be generated.  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 environment.  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 exe-
	      cutes.

       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 configuration will be exceeded.

RESTRICTIONS

       Note, that the functionality of any checkpointing, migration or restart procedures provided by default with the Sun Grid  Engine  distribu-
       tion  as  well as the way how they are invoked in the ckpt_command, migr_command or restart_command parameters of any default checkpointing
       environments should not be changed or otherwise the functionality remains the full responsibility  of  the  administrator  configuring  the
       checkpointing environment.  Sun Grid Engine will just invoke these procedures and evaluate their exit status. If the procedures do not per-
       form 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 permissions.

SGE 6.2u5							      $Date$							     CHECKPOINT(5)