Storage Hierarchy Design in Video-on-Demand Servers

This paper proposes a design procedure that exploits storage devices with diierent cost/bandwidth and cost/capacity ratios to build a hierarchical storage system for video-on-demand with minimum cost. The storage system is assumed to have two levels of hierarchy. The level-1 storage devices feature a low cost/bandwidth ratio and a high cost/capacity ratio. On the other hand, the level-2 storage devices feature a high cost/bandwidth ratio and a low cost/capacity ratio. The proposed procedure determines, with respect to overall system cost, which level of the hierarchy each program should be placed into. Based on the decisions, the designer then can gure out the appropriate connguration of the hierarchical storage system. The optimization target is to minimize the overall cost of the storage system.