Constant and Random Full Backup Models with Incremental and Differential Backup Schemes

Abstract

It has been commonly known in a Database Management System that constant plans of incremental/differential backup schemes are set up and their full backups should be done to balance the costs of data backup and failure recovery. In this paper, we consider a database system that is running for 24/7 and has several random busy states of updates, and we suppose that incremental/differential backups are implemented after each update and full backups are triggered at constant time T and random updates N. That is, models with decision variables of T and N for full backups with random incremental/differential backups are considered. We obtain the expected costs of data backup and failure recovery and the expected cost rates for full backups. Optimum solutions to minimize the expected cost rates are discussed in analytical ways. Furthermore, full backups that are made at time T and updates N are considered as constant and random modes respectively and compared analytically. For the discussions, numerical examples in exponential cases are given.