A SOLUTION PROCEDURE FOR THE FILE ALLOCATION PROBLEM WITH FILE AVAILABILITY AND RESPONSE-TIME

A major design issue facing the designer of a distributed computing system involves the dertermination of the number of file copies and their locations in the distributed environment. This problem is commonly referred to as the file allocation problem (FAP). In this paper, a FAP model is formulated that seeks to obtain the lowest cost file allocation strategy. The model ensures, for all on-line queries, the attainment of acceptable levels of (i) response times during peak demand periods, and (ii) file availability. Unlike previous FAP research, the proposed model treats response time on a query-by-query basis, and not as a single, system-wide average delay constraint. Similarly, file availability is treated on a file-by-file basis. A branch-and-bound solution procedure is proposed for solving the resulting 0/1 integer programming problem to optimality. Results of computational experiment with the proposed solution procedure are reported.