Cost, Speed, and Reliability Tradeoffs between N+1 UPS Configurations

There is an increasing trend towards N+1 UPS architectures – rather than 2N – as IT fault tolerance through software continues to improve. There are two common ways N+1 can be achieved: paralleling multiple unitary UPSs together or deploying a single UPS frame with multiple internal modules configured for N+1 redundancy. In this paper, we quantify key tradeoffs between an internal “modular” redundant UPS and parallel redundant UPSs, and show a 27% capital cost savings and a 1-2 week decrease in deployment time when internal redundancy is deployed. We also discuss the importance of fault tolerance within the UPS to ensure availability, reliability, and maintainability needs are met. Revision 2 White Paper 234