language: en

Storage Systems for Movies-on-Demand Video Servers

Ann L. Chervenak
April 7, 1995

1 Abstract In this paper, we evaluate storage system alternatives for movies-on-demand video servers. We begin by characterizing the movies-on-demand workload. Then we study disk farms in which one movie is stored per disk. This is a simple scheme, but it wastes substantial disk bandwidth, since disks holding less popular movies are under-utilized; also, good performance requires that movies be replicated to reflect the user request pattern. Next, we examine disk farms in which movies are striped across disks, and find that striped video servers offer close to full utilization of the disks by achieving better load balancing. Finally, we evaluate the use of storage hierarchies for video service that include a tertiary library along with a disk farm. Unfortunately, we show that the performance of neither magnetic tape libraries nor optical disk jukeboxes as part of a storage hierarchy is adequate to service the predicted distribution of movie accesses. We suggest changes to tertiary libraries that would make them better-suited to these applications.

2 Introduction