Techniques for increasing the stream capacity of a high-performance multimedia server

Abstract

High-performance servers and high-speed networks will form the backbone of the infrastructure required for distributed multimedia information systems. A server for an interactive distributed multimedia system may require thousands of gigabytes of storage space and high I/O bandwidth. In order to maximize system utilization and, thus, minimize cost, it is essential that the load be balanced among each of the server's components viz., the disks, the interconnection network, and the scheduler. Many algorithms for maximizing retrieval capacity from the storage system have been proposed in the literature. This paper presents techniques for improving server capacity by assigning media requests to the nodes of a server so as to balance the load on the interconnection network and the scheduling nodes. Five policies for request assignment - round-robin (RR), minimum link allocation (MLA), minimum contention allocation (MCA), weighted minimum link allocation (WMLA), and weighted minimum contention allocation (WMCA) - are developed. The performance of these policies on a server model developed earlier is presented. We also consider the issue of file replication, and develop two schemes for storing the replicas, the Parent Group Based Round-Robin Placement (PGBRRP) scheme, and the Group Wide Round-Robin Placement (GWRRP) scheme. The performance of the request assignment policies in the presence of file replication is presented.