Video allocation methods in a multi-level server for large-scale VOD services

Although the characteristics of a hard disk are more suitable for the interactive environment of a VOD service, using hard disks as permanent storage devices can suffer from the relatively high cost and frequent failure rate of a hard disk. Several VOD servers with tertiary storage devices have been proposed but the response time for a user's request in most approaches is too long to he used in the interactive environment of a VOD service. This paper proposes another structure of a VOD server that utilizes the jukeboxes of optical disks for a video database. Since the jukeboxes of optical disks are more reliable and inexpensive, it is useful for storing the huge volume of video streams. As a result, it can he a part of a cost-effective server configuration for large-scale VOD services. Several allocation methods for video streams in the jukeboxes are devised and compared in order to improve the performance of the proposed structure.