A novel video layout strategy for near-video-on-demand servers

Abstract

Near-video-on-demand (NVOD) provides different a service from true video-on-demand (VOD). Since the NVOD service needs to be much cheaper than the VOD service, it is important to minimize the server's cost. In this paper, we present a novel video layout strategy for NVOD servers that enforce sequential disk access. Thus, the disk bandwidth is optimally utilized. We define a model that analyzes the storage subsystem behavior, buffer requirements and usage. Strategies that match the actual disk bandwidth to the application bandwidth requirements are developed. Using this layout strategy, each disk can deliver 50% more streams than a VOD system can, and memory buffers are reduced by almost half. Since disks and memory account for a significant portion of the total system cost in a video server, using these strategies significantly reduces server costs. An NVOD server prototype was built that supports both "broadcast" and "on-demand" service models. Using this prototype, we have demonstrated that our proposed layout strategies are practical.