影响多媒体服务器性能的关键因素研究

在构建大规模视频服务系统时 ,基于层次型多服务器群的体系结构在吞吐率、可扩展性、经济性等方面都有其突出的优势 ,尤其适合于在因特网上的应用 .但是 ,要充分发挥和提高视频服务系统的性能 ,还要针对一些主要的瓶颈(如服务器磁盘 I/ O带宽与网络带宽 ) ,解决好一系列的问题 .本文分析了影响多媒体视频服务器性能的一些主要因素 ,如视频服务器的体系结构、服务器与客户端之间的数据传送方式、媒体数据在视频服务器存储子系统中的分布与放置方式、对磁盘访问请求的调度、单服务器中的缓存及多服务器间协同缓存的管理、接入控制策略、流调度策略等 ,这些因素对视频服务器的性能与吞吐率有着极大的影响 .本文还介绍了一些适用于大规模视频服务系统的性能优化技术 ,如广播、批处理等流调度策略 .在构建视频服务器系统时 ,只有综合考虑这些因素 ,才能真正提高服务器乃至整个视频服务系统的吞吐率 ,并较好地满足客户的 Qo S要求

Research on Key Influencing Factors on Multimedia Servers

In building large-scale video service systems, the architecture based on hierarchical multi-server clusters has prominent advantages in server throughput, scalability, cost-effectiveness, etc. It is especially suitable for applications over the Internet. To fully raise and utilize the performance of video service systems, however, it is necessary to do some work on the major bottlenecks, such as server disk I/O bandwidth and network bandwidth. This paper analyzes some major factors affecting the performance of video servers, including servers' architecture, data delivery scheme between server and clients, the distribution and placement of media data in video servers' storage sub-system, scheduling of disk access requests, the management of single server's cache and cooperative cache of multi-servers, admission control strategies, stream scheduling strategies. These factors have important influence on the performance and throughput of video servers. Several performance optimizing strategies for large-scale video service systems are also presented, such as broadcasting, batching techniques. When constructing video servers, it is only after considering all these factors synthetically that their performance and throughput will be really raised up, and the QoS requirements of the clients can be met satisfactorily.