These two words are usually used to describe high availability infrastructure and server architectures, but it is nonetheless easy to get confused when trying what they really mean.

What is Resilience ?

“Resilience” is often used to describe network with an “active – active” setup. A good example is how we use multiple network links to different locations: each link always has available capacity to handle failure in another link. During a failure situation, traffic will be routed over the working link, but the end-user will not experience any difference on service availability.

What is Redundancy ?

“Redundancy” means that you have an extra unit of something which can be put into use when necessary. With redundant PSU, the server only utilizes one PSU at a time, but if the primary PSU fails, the secondary PSU will be ready to take over.