Infrastructure is disclosed for optimizing performance and minimizing errors during normal operation of replicated data centers. In some implementations, systems that are replicated in each data center under a common IP address may have service requests routed to them using routing tables that favor one of the systems. The routing tables may prefer the system that resides in the data center where the service requests originated, or they may prefer the system that meets other criteria. Other systems replicated in the data center may have service requests routed to them using configuration tables that favor one of the systems. The configuration tables may also prefer the system that resides in the data center where the service requests originated, or they may prefer the system that meets other criteria. This arrangement helps optimize performance during normal operation and minimize potential for disruption of service should one of the data centers fail.