Load-Balanced Data Placement for Variable-Rate Continuous Media Retrieval

Continuous media storage systems must provide guaranteed services and require large amount of resource consumption in terms of storage capacity and transmission band-width. In this chapter, we focus on a placement scheme for continuous media storage systems in a multimedia database management system to provide the load balance of disks uniformly. In particular, we consider complete control over the session presentation using VCR-like functions such as fast-forward and rewind. We propose an improved round-robin placement scheme, called prime round-robin (PRR), in a disk-array-based system to remove hot spots for variable-rate retrievals. In addition, we describe a disk group partitioning scheme to improve reliability and interactivity of the storage system. Since loads of the individual disks are uniformly distributed for any rate of retrieval in PRR, the service quality is superior to other placement schemes with regard to the miss ratio, the number of users admitted, and the required buuer size. Various simulation results are also presented.