QoS-aware object replica placement in CDNs

Recently, content distribution networks (CDNs) have attracted a great deal of attention from both the industry and academic communities. We design efficient object replication algorithms to achieve the optimal performance while not violating clients´ QoS requirements in CDN. We use a three-stage mechanism: first, object replication constraints to meet the QoS requirements are generated; second, a minimal object replication set (MORS), which can satisfy the constraints with the minimal number of replicas on each server, is created; and finally, more objects are replicated on the servers with spare space to further improve the performance. We propose a number of heuristic algorithms and conduct trace-driven experiments to evaluate the performance