Management of physical replicas in parallel multimedia information systems

Abstract

Multimedia information systems have emerged as an essential component of many application domains ranging from library information systems to entertainment technology. However, most implementations of these systems (based on a workstation) cannot support a continuous display of multimedia objects and suffer from frequent disruptions and delays termed hiccups. This is due to the low I/O bandwidth of the current disk technology, the high bandwidth requirement of multimedia objects, and the large size of these objects which requires them to be almost always disk resident. One approach to resolve this limitation is to decluster a multimedia object across multiple disk drives in order to employ the aggregate bandwidth of several disks to support its continuous retrieval (and display). To support simultaneous display of several multimedia objects for different users, the system can replicate data across multiple groups of disk drives in a virtual manner. This paper describes techniques to manage the replicas of objects in a parallel multimedia information system. These techniques are general and can be customized by the database administrator to satisfy the constraints of an application. We quantify the tradeoffs associated with these strategies using a simulation study.