A Comparative Study on Replica Placement Algorithms for Content Delivery Networks

In today´s web based IT environment response time and availability are of major concerns, a few seconds delay in response time or non-availability of a resource can significantly impact customer satisfaction. Replication provides better performance and higher availability by maintaining multiple copies of data called replicas at various strategic locations. An important issue that must be addressed before replication is performed is where to place replicas. Several replica placement algorithms have been proposed and each has its own advantages and disadvantages. In this paper we study the various replica placement algorithms with respect to content delivery networks. Our main contribution in this paper is to compare popular replica placement algorithms and provide general scenarios for content delivery networks with proposed suitable algorithm for each of the scenarios. The scenarios can be a reference point for system designer for choosing a right replica placement algorithm for content delivery networks.