Data replication is an excellent technique to move and cache data close to users. By replication, data access performance can be improved dramatically. One of the challenges in data replication is to select the candidate sites where replicas should be placed. We use a multiobjective model to address the replica placement problem. The multi-objective model considers the objectives of p-median and p-center models simultaneously to select the candidate sites that will host replicas. The objective of the p-median model is to find the locations of p possible candidate replication sites by optimizing total (or average) response time; where the pcenter model finds p candidate sites by optimizing maximum response time. A Grid environment is highly dynamic so user requests and network latency vary constantly. Therefore, candidate sites currently holding replicas may not be the best sites to fetch replica on subsequent requests. We propose a dynamic replica maintenance algorithm that re-allocat...
Rashedur M. Rahman, Ken Barker, Reda Alhajj