A survey of peer-to-peer overlay approaches for networked virtual environments
Multi-player Online Games (MOGs) have emerged as popular data intensive applications in recent years. Being used by many players simultaneously, they require a high degree of fault tolerance, scalability and performance. In this paper we analyze how database replication can be used in MOGs to achieve these goals. In data replication, clients can read data from any database replica while updates have to be executed at all available replicas. Thus, reads can be distributed among the replicas leading to reduced response time and scalability. Furthermore, the system is fault-tolerant as long as a replica is available. However, we are not aware of any previous study on the application of database replication to MOG. In this paper, we present a system, MiddleSIR, which provides database replication support. We illustrate different replication protocols implemented in the system along an example, explaining how data consistency and fault tolerance can be achieved. From there, we design a small multi-player typing game to demonstrate how to apply database replication to MOG. We will discuss how different replication protocols affect the semantics of the game. Our experiments show that database replication can provide good scalability and performance in both Local Area Networks (LAN) and Wide Area Networks (WAN).