A Simulation Approach for Evaluating Scalability of a Virtually Fully Replicated Real-time Database

We use a simulation approach to evaluate large scale resource usage in a distributed real-time database. Scalability is often limited by that resource usage is higher than what is added to the system when a system is scaled up. Our approach of Virtual Full Replication (VFR) makes resource usage scalable, which allows large scale real-time databases. In this paper we simulate a large scale distributed real-time database with VFR, and we compare it to a fully replicated database (FR) for a selected set of system parameters used as independent variables. Both VFR and FR support local timeliness of transactions by ensuring local availability for data objects accessed by transactions. The difference is that VFR has a scalable resource usage due to lower bandwidth usage for data update replication. The simulation shows that a simulator has several advantages for studying large scale distributed real-time databases and for studying scalability in resource usage in such systems.