AN ONLINE ALGORITHM FOR CHECKPOINT PLACEMENT

Checkpointing enables us to reduce the time to recover from a fault by saving intermediate states of the program in a reliable storage. The length of the intervals between checkpoints affects the execution time of programs. On one hand, long intervals lead to long reprocessing ti me, while, on the other hand, too frequent checkpointing leads to high checkpointing overhead, In this paper, we present an on-line algorith m for placement of checkpoints. The algorithm uses knowledge of the cu rrent cost of a checkpoint when it decides whether or not to place a c heckpoint. The total overhead of the execution time when the proposed algorithm is used is smaller than the overhead when fixed intervals ar e used. Although the proposed algorithm uses only on-line knowledge ab out the cost of checkpointing, its behavior is close to the of-line op timal algorithm that uses a complete knowledge of checkpointing cost.