Analysis And Improvement Of Grid Simulator OptorSim

Grid technology tries to integrate the computing resources, storage resources, devices and equipments, etc. over the wide area network into a uniform and efficient service entity. Designing a grid system is very complex because there are many factors constrained, i.e. the dynamic, heterogeneous of global resources and efficiency of the whole system. The grid simulator provides a great facility to help the designer in verifying the design and performance.This article has introduced several kind of grids simulators and has mainly studied in OptorSim about the transcription replacement questionReplacement transposition is to solve the problem that when there is not enough space to store new copies, how to delete existent copies. Base on the different strategies between creation and transposition, the replication optimization algorithm contains No Replication(NR), Least Recently Used(LRU), Least Frequently Used(LFU) and Economy-Based replication Strategy(EBRS). Besides, we aim at the disadvantages of LFU, adding improved algorithm MFU.Grid simulator OptorSim is used to analyse the capability of MFU and LFU about three aspects, such as the scheduling algorithms, the access patterns , the number of jobs. The result of examination indicates that improved MFU optimization algorithm takes precedence of LFU in certain grid environment.The above work is theratically and practically important to research the optimisation of the grid repica. The research methods are worthy to generalize. On one hand, the classical page replacement algorithms in operating system can be transformed into grid environment. On the other hand, new replica optimisation algorithms can be designed and compared with old algorithms in performance and shortcomings. .