An evaluation of VBR disk admission algorithms for continuous media file servers

Abstract

In this paper, we address the problem of choosing a disk admission algorithm for continuous media streams where each stream may have a different bit rate, and more importantly, where the bit rate within a single stream may vary considerably. We evaluate several different Variable Bit Rate (VBR) disk admission control algorithms for continuous media. An algorithm which accepts too few streams under-utilizes the server resources, while an algorithm which accepts too many streams over-utilizes the resources resulting in inadequate service (i.e. missing or delayed data) to the clients. The evaluation process is based on a representative set of video streams encoded in MJPEG. We conclude that one particular algorithm, the VBR simulation algorithm, performs the best among realizable algorithms in terms of system utilization and delivery guarantees and performs close to an optimal algorithm,