kcs @ cs.toronto.edu

We introduce an algorithm that uses bufJer space available at the server for smoothing disk transfers of variable bit-rate streams. Previous smoothing techniques prefetched stream data into the client buffer space, instead. However, emergence of personal computing devices with widely different hardware configurations means that we should not always assume abundance of resources at the client side. The new algorithm is shown to have optimal smoothing effect under the specified constraints. We incorporate it into a prototype server, and demonstrate significant increase in the number of streams concurrently supported at different system scales. We also extend our algorithm for striping variable bit-rate streams on heterogeneous disks. High bandwidth utilization is achieved across all the different disks, which leads to server throughput improved by severalfactors at high loads. 1

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

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 supportisprovided 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