June 18, 2014
Traditionally, data center operators and IT professionals have used a very simple process to create a safe “A” side to “B” side failover scenario. The process and math are very straight forward. The user decides what a safe threshold is - typically 80% of the total kVA of the enclosure - and divides that value evenly between both rack power strips and their onboard circuit breakers. Due to the relative simplicity of the architecture, this practice can work well in a single-phase, less than 5kVA environment. However, in power kVA environments greater than 5kVA, and more complex three-phase environments that are now typical for blade and high density environments, this practice dramatically increases the likelihood of encountering a cascading failure and creates the additional downside of stranding large amounts of available space, power and cooling resources in the process.