Minimizing access cost of replicas in tree data grids for read-only objects

Replication of objects is a popular solution to reduce access cost, to increase network usage and objects availability. In order to achieve these goals Optimal Number of Replicas (ONR), Greedy and Simple Greedy algorithms with suitable time complexity, are proposed. Our algorithms are evaluated in three performance parameters: Normalized Access Cost, Effective Network Usage and Percentage of Local Access. Results from experiments reveal that the proposed algorithms have significant improvements in the decreasing access cost, increasing network usage, and enhancing objects accessibility. The results also show that the ONR algorithm has the better performance than the Greedy algorithm, in turn, better than the Simple Greedy algorithm.