Modular and Efficient Resource Management in the Exedra Media Server

Explosive growth in online services has recently renewed the interest for building modular and efficient network server systems. System design complications coupled with excessive expectations from technological progress previously discouraged the development of media servers efficiently supporting video streams with variable bit rates. In this paper, we describe the design of a distributed media server architecture, and the implementation details of a prototype. Native support is provided for variable bit rate streams, by considering their special features in the resource management policies. We identify several problems, and propose new approaches for scheduling the playback requests, organizing the memory buffers, allocating the storage space, and structuring the disk metadata. We justify several of our decisions with comparative performance measurements using both synthetic benchmarks and actual experiments with variable bit rate MPEG-2 streams over SCSI disks.