Design issues on media server scheduling for video-on-demand (VoD) services

Media server scheduling in video-on-demand (VOD) systems includes video content allocation and request migration among servers. In this paper, we present a greedy algorithm to allocate video copies to media servers. It uses a graph model and minimizes the average shortest distance among media servers at each step. To facilitate the performance analysis of the random early migration (REM) algorithm proposed in our previous work, we introduce a formal description of the media service. Based on this system formalization, we develop a state transition method to study the parameter effect on the REM performance and compare the real time performance between REM and traditional migration with early start (TMES). The analytical result shows that REM introduces smoother migrations between media servers and thus leads to less real time system load than TMES.