Constrained-Latency Storage Access: A Survey of Application Requirements and Storage System Design Approaches

Applications with Constrained Latency Storage Access (CLSA) are those that have large storage needs and hard constraints on the amount of latency they can tolerate. Such applications present a problem when the storage technology that is cost effective and large enough cannot meet their latency constraints for demand fetching. Examples are found in the developing field of multimedia computing and, to a lesser extent, in real-time database literature. This paper examines the nature of timing constraints at the application-storage interface and defines a classification for both the synchronization constraints of the application and the latency characteristics of the storage system. This classification is then used to survey existing approaches to CLSA and to assess their limitations. The more promising technologies are identified, and their suitability for integration into a general purpose storage management system to meet CLSA needs is examined.