On the optimality of disk allocation for Cartesian product files (extended abstract)

摘要

In this paper we present a coding-theoretic analysis of the disk allocation problem. We provide both necessary and sufficient conditions for the existence of strictly optimal allocation methods. Based on a class of optimal codes, known as maximum distance separable codes, strictly optimal allocation methods are constructed. Using the necessary conditions proved, we argue that the standard definition of strict optimality is too strong, and cannot be attained in general. A new criterion for optimality is therefore defined whose objective is to design allocation methods that yield a response time of one for all queries with a minimum number of specified attributes. Using coding theory, we determined this minimum number for binary files, assuming that the number of disks is a power of two. In general, our approach provides better allocation methods than previous techniques.