SORD: a new strategy of online replica deduplication in Cloud-P2P

In online Cloud-P2P system, more replicas can lead to lower access delay but more maintenance overhead and vice versa. The traditional strategies of online replica deduplication usually utilize the method of dynamic threshold to delete the redundant replicas. Since the replicas access amount has varied over time, and every replica can bear a certain amount of requests, the replica of being deleted may impact on other nodes, lead to these nodes overload, deteriorating the system performance. But this impact is not paid enough attention in the traditional strategy. To deal with the problem, this paper proposes a new strategy of online replica deduplication (SORD), achieving to reduce the impact on other nodes when deleting a redundant replica. In order to reduce the impact, SORD adopts the method of prediction evaluation to delete the redundant replica. Before deleting a replica, it applies the method of fuzzy clustering analysis to get the optimal deletion replica from the file’s replica set. Based on the historical visiting information of the optimal deletion replica and the capacity of nodes, SORD evaluates the impact on other nodes to decide whether a replica can be deleted. Extensive experiments demonstrate that SORD obtains superior performances in access latency around 5–15% on average and better load balance than other similar methods. Meanwhile, it can remove about 65% redundant replicas.