A Data Placement Method of HSM for Streaming Media Server in Network Environment

Abstract

Streaming media service, such as video-on-demand (VOD), is getting popular in network environment. To get high cost/performance ratio, Hierarchical Storage Management (HSM) is adopted by streaming media servers in such services. However, if HSM system places the media object, say a movie, exclusively in a tertiary storage device, the response time to an on demand service will be too long to be satisfactory. This paper presents a new data placement method based on prearrangement strategy in HSM for streaming media server. By prearranging the head part of media objects on disk, streaming data accesses can get immediate response, and in concurrent, tertiary storage device can be prepared for continuous access. The paper discusses a method to calculate the head data length of media objects and an algorithm to read data in HSM. Simulation result shows that with a low disk storage cost, the response time of the HSM system can be reduced to a large extent, and the performance of the whole system is enhanced significantly.