Allocating primary and back-up copies of databases in distributed computer systems: A model and solution procedures

Given an existing set of computer installations, determining database partitions, and allocating one or more copies of these partitions among computer installations, is a challenging problem frequently faced by designers of distributed computer systems. In this paper, the database partitioning and allocation problem is studied for a class of organizations that not only have widely dispersed operations and localized information demands, but also are cricially dependent on their computer systems for their operations. This dependence on the availability of their information systems necessitates online back-up copies of their databases. A realistic model capturing many important facets of this problem is presented. An efficient solution procedure is outlined and computational experience with this procedure is reported. The use of the model in designing distributed computer systems is demonstrated with an example.