• replica placement;
  • data grids;
  • quality-of-service;
  • greedy-cover algorithm;
  • simulated-annealing algorithm


In this paper, we consider the QoS-aware replica placement problem. Although there has been much research on the problem, most approaches focus on the average system performance and ignore the quality assurance issue. However, quality assurance is crucial, especially in heterogeneous environments. To fill this research gap, we proposed four heuristic algorithms to determine the locations of replicas in order to satisfy the quality requirements imposed by data requests. Three of the algorithms are greedy heuristics called Greedy-Cover, Cover-Partition and Multi-Source. The fourth algorithm is based on the Simulated Annealing technique. Our experiment results indicated that Greedy-Cover and the Simulated Annealing-based algorithms can find effective solutions efficiently. Copyright © 2011 John Wiley & Sons, Ltd.