MediaGuard: a model-based framework for building streaming media services

A number of technology and workload trends motivate us to consider the appropriate resource allocation mechanisms and policies for streaming media services in shared cluster environments. We present MediaGuard – a model-based infrastructure for building streaming media services – that can efficiently determine the fraction of server resources required to support a particular client request over its expected lifetime. The proposed solution is based on a unified cost function that uses a single value to reflect overall resource requirements such as the CPU, disk, memory, and bandwidth necessary to support a particular media stream based on its bit rate and whether it is likely to be served from memory or disk. We design a novel, segment-based memory model of a media server to efficiently determine in liner time whether a request will incur memory or disk access when given the history of previous accesses and the behavior of the server’s main memory file buffer cache. Using the MediaGuard framework, we design a novel, more accurate admission control policy for streaming media servers that accounts for the impact of the server’s main memory file buffer cache. Our evaluation shows that, relative to a pessimistic admission control policy that assumes that all content must be served from disk, MediaGuard delivers a factor of two improvement in server throughput.