Random Inspection Policies for a Database System

When failure occurs in a database, we execute the backup operations to the latest checking times. We formulate periodic and random inspection policies for a database. When the system is checked at the N th interval of working times, two total expected costs are obtained and optimal numbers N* which minimize them are derived analytically, when failure and random times are exponential. One modified backup model in which failures are detected only at checking times is proposed and two expected costs are obtained.