Report Number: CSL-TR-97-723
Institution: Stanford University, Computer Systems Laboratory
Title: Hierarchical Storage Systems for Interactive Video-On-Demand
Author: Chan, Shueng-Han Gary
Author: Tobagi, Fouad A.
Date: April 1997
Abstract: On-demand video servers based on hierarchical storage systems are able to offer high-capacity and low-cost video storage. In such a system, video files are stored in the tertiary level and transferred to the secondary level to be displayed. Designing such servers allowing user interaction with the playbacked video is of great interest. We have conducted a comprehensive study on the architecture and operation of such a VOD server. Our objective is to understand its performance characteristics, so as to design a video server to meet specific application requirements. Applications of interest include distance-learning, movie-on-demand, interactive news, home-shopping, etc. The design of such a server actually involves many design choices pertaining to both architecture and operational procedures. We first study through simulation a baseline system which captures the essential performance characteristics of a hierarchical storage system. Then we extend our study beyond the baseline covering numerous other system variations in terms of architectural parameters and operational procedures. We have also examined various applications characteristics, such as file size and video popularity, on system performance. We demonstrate the usefulness of our results by applying them to the design of a video server taking into account current storage technologies.