Damage assessment for optimal rollback recovery

Conventional schemes of rollback recovery with checkpointing for concurrent processes have overlooked an important problem: contamination of checkpoints as a result of error propagation among the cooperating processes. Error propagation is unavoidable due to imperfect detection mechanisms and random interprocess communications, and it could give rise to contaminated checkpoints which, in turn, result in unsuccessful rollbacks. To counter the problem of error propagation, a damage assessment model is developed to estimate the correctness of saved checkpoints under various circumstances. Using the result of damage assessment, determination of the “optimal” checkpoints for rollback recovery-which minimize the average total recovery overhead-is formulated and solved as a nonlinear integer programming problem. Integration of damage assessment into existing recovery schemes is also discussed