The emergence of various multimedia applications, service and devices, multimedia delivery is expected to become the major traffic of Internet which will keep increasing rapidly. In order to serve such large scale multimedia applications, more and more service providers store their video assets in the cloud and delivery streaming to their consumers cross cloud, for example, YouTube. Along with the growth of user and the amount of media content constantly being produced, traditional cloud-based storage has two drawbacks. First, a lot of servers and storages devices are needed, which could easily be the performance bottleneck in the whole system. Second, to provide differential classes of services in the large-scale situation, system tends to need many additional devices.