Study Of Optimization Technique Of System Performance Based On Checkpoint

Today computer systems are widely used in transportation, medical, navigationand many other fields. Human beings’ demand on systems reliability is increasingsignificantly. In fact, software and hardware characteristics decide that it is impossiblesystems do not fails during the whole process. Considering a long-running task, if afailure happens during the running time, the task must be restarted. So fault tolerance isparticularly important. As an effective means for fault tolerance, checkpoint/restart iswidely used in computer and database systems to improve the system reliability. TheCheckpoint/Restart technology is used to avoid significant loss of computation when afailure happens to improve the system performance.Aiming at the high performance overhead problem in the one-level recoveryscheme, Vaidya proposed the so-called two-level checkpoint recovery schemes todecrease the overhead which is incured during the process of setting up checkpoints. Inthe two-level recovery scheme, there exist two types of checkpoints which areN-checkpoint and local checkpoint and saved in stable and local disk respectively. Theoverhead of setting a local checkpoint is lower than an N-checkpoint. To obtain theoptimal performance, Vaidya determine the checkpoint placement by numerical search.The paper presents a two-level checkpoint placement strategy which decides tohow to place local checkpoint and N-checkpoint in the whole process. The placementstrategy can not only apply to exponential failure distribution but also more complexfailure distribution type, such as Weibull. The result shows the scheme presented canperform good performance. Meanwhile, we also analyze the factors which affect theoptimal number of local checkpoints between N-checkpoints and the result shows thecheckpoint ratio and the probability is the influences factors.