Description
Object replication is a well-known technique to improve performance of a distributed Web-server system. This article first presents an algorithm to group correlated Web objects that are most likely to be requested by a given client in a single session so that they can be replicated together, preferably, on the same server. A centralized object replication algorithm is then proposed to replicate the object groups to a cluster of Web-server systems in order to minimize the user’s perceived latency, which is subject to certain constraints. Due to the dynamic nature of Web content and users’ access patterns, a distributed object replication algorithm also is proposed where each site locally replicates the object groups based on the local access patterns. The performance of the proposed algorithms is compared with three well-known algorithms, and the results are reported. The results demonstrate the superiority of the proposed algorithms.