Redundancy in data centers is critical to ensure high availability and fault tolerance. The term "2N+1" is a specific redundancy configuration that provides a very high level of reliability: 1. **Basic Concept**: - "N" represents the necessary capacity required for normal operation. For example, if you need 1 generator to run your data center, "N" equals 1. 2. **2N Configuration**: - "2N" means having two independent systems, each capable of handling the full load of the data center. This ensures that if one system fails, the other can take over without any downtime. 3. **+1 Addition**: - The "+1" means there is an additional spare capacity on top of the 2N configuration. This spare capacity acts as a backup for any component within the 2N systems, providing an extra layer of redundancy. ### Example: If a data center requires 2 generators to function (N=2), then a 2N+1 configuration would have: - 2 complete and independent sets of generators (2N = 4 generators total). - An additional generator as a backup (+1). So, in total, a 2N+1 setup would have 5 generators. This ensures that the data center can handle multiple failures without interruption.