A performance study of dynamic replication techniques in continuous media servers

The stringent requirements of multimedia applications make design of cost-effective and scalable systems difficult; thus, efficient adaptive and dynamic resource management techniques can be of great help in improving performance and scalability characteristics of such systems. In this paper we focus on threshold-based policies for dynamic resource management in the context of continuous media (CM) servers; we do this without any knowledge of data access patterns and with provisions for full use of VCR functionality. We propose a mathematical model of user behavior and show through a performance study, that not only does the use of this model in conjunction with dynamic resource management policies improves the system´s performance but that it also facilitates significantly reduced sensitivity to changes in: (a) system architecture, (b) workload characteristics, (c) skewness of data access patterns, (d) frequency of changes in data access patterns, and (e) choice of threshold values. We believe that not only is this a desirable property for a CM server, in general, but that furthermore, it suggests the usefulness of these techniques across a wide range of continuous media applications