Dynamic replication algorithms for the multi-tier Data Grid

Data replication is a common method used to improve the performance of data access in distributed systems. In this paper, two dynamic replication algorithms, Simple Bottom-Up (SBU) and Aggregate Bottom-Up (ABU), are proposed for the multi-tier Data Grid. A multi-tier Data Grid simulator called DRepSim is developed for studying the performances of the dynamic replication algorithms. The simulation results show that both algorithms can reduce the average response time of data access greatly compared to the static replication method. ABU can achieve great performance improvements for all access patterns even if the available storage size of the replication server is very small. Comparing the two algorithms to Fast Spread dynamic replication strategy, ABU proves to be superior. As for SBU, although the average response time of Fast Spread is better in most cases, Fast Spread's replication frequency is too high to be applicable in the real world.