Proposing and evaluating dynamic data replication strategy in data grid environment

A Data Grid consists of a collection of geographically distributed computer and storage resources located in different places, and enables users to share data and other resources. Data replication is used in Data Grid to enhance data availability, fault tolerance, load balancing and reliability. Although replication is a key technique, but the problem of selecting proper locations for placing replicas i.e. replica placement in Data Grid has not been widely studied, yet. In this paper an efficient replica selection strategy is proposed to select the best replica location from among the many replicas. Due to the limited storage capacity, a good replica replacement algorithm is needed. We present a novel replacement strategy which deletes files in two steps when free space is not enough for the new replica. A Grid simulator, OptorSim, is used to evaluate the performance of this dynamic replication strategy. The simulation results show that the proposed algorithm outperforms comparing to than the existing algorithms mentioned in literature as number of jobs increases.