*Department of Mathematics, T.I.T. S., Bhiwani, Haryana, India, E-mail: amitmanocha80@yahoo.com
**Department of Computer Science, N.C.C.E., Panipat, Haryana, India, boora_s@yahoo.com
***Former Prof., JRE Group of Institution, Greater Noida, (U.P.), India, dranil_tan@rediffmail.com
A discrete state space and continuous parameter stochastic model for two unit hot standby database system with standby database under constant observation of database administrator (DBA) has been developed. The primary unit is synchronized with hot standby unit through online transfer of archive redo logs. Standby database unit is always kept under constant observation of DBA to check either its synchronization with primary unit is working properly or not. Failure of database unit either primary or standby is also dealt by of DBA. The system is analyzed by making use of semi-Markov process and regenerative point technique. Mathematical expressions for various performance indicating measures of the system has been obtained and economic analysis has been done. Numerical examples are also discussed on the basis of data collected to illustrate the behavior of model developed. Bounds for various costs pertaining to the profitability of the system have also been obtained.
Database system, hot standby, constant observation, semi-Markov processes, regenerative point technique
