file replication in video on demand services
A large-scale video-on-demand (VOD) system demands storage of hundreds of movies and support of thousands of concurrent accesses. The number of concurrent accesses to each movie may vary, depending on the popularity of each movie. File replication problem is concerned with how to replicate, and place the movie files over a number of magnetic disk arrays such that a given access profile can be supported at a minimum cost. This is an NP-hard combinatorial problem. However with its similarity to a transportation model, we develop a transportation-type algorithm to generate a good solution in an effective and convenient form. The computational results show that the proposed algorithm outperforms the existing greedy placement algorithm.
file replication video on demand concurrent accesses disk arrays transportation model northwest corner rule storage capacity i/o bandwidth