Striping Doesn't Scale: How to Achieve Scalability for Continuous Media Servers with Replication

Abstract

Multimedia applications place high demands for QoS, performance, and reliability on storage servers and communication networks. These, often stringent, requirements make design of cost-effective and scalable continuous media (CM) servers difficult. In particular, the choice of data placement techniques can have a significant effect on the scalability of the CM server and its ability to utilize resources efficiently. In the recent past, a great deal of work has focused on ``wide'' data striping as a technique which ``implicitly'' solves load balancing problems; although, it does suffer from multiple shortcomings. Another approach to dealing with load imbalance problems is replication. The main focus of this paper is a study of scalability characteristics of CM servers as a function of tradeoffs between striping and replication. More specifically, striping is a good approach to load balancing while replication is a good approach to ``isolating'' nodes from being dependent on other system resources. The appropriate compromise between the degree of striping and the degree of replication is key to the design of a scalable CM server. This is the topic of our work. Also cross-referenced as UMIACS-TR-99-45