A Selective Mirrored Task Based Fault Tolerance Mechanism for Big Data Application Using Cloud

Table 1

Cost optimization factors.

Symbols	Definitions
	a scientific application
	DAG of the tasks in
	the critical path of
	the -th subtask in
	the weight of -th tasks in
	the set of in
	data dependence from to
	the set of
	the time to make a check-point file
	the optimal check-point interval
	the practical completion time for the task
	the time to read a check-point file
	the time before a failure in an interval
	the computation time for a task
	a schedule which maps the tasks to processors
	the weight of
	the predecessor subtasks set of in
	the successors subtasks set of in
	the next subtask on the same processor
	the finish time of on the
	the earliest start time of on the
	the latest finish time of on the
	the slack time of on the
	the indirect slack time of on the
	denotes the quantitative importance of
	The threshold of
	The set of key subtasks
	The makespan of the application