Any good system targeting the public or the private audience must be built to expect the unexpected. There are no perfect systems, and at some point, something will happen that will render a system inoperative, such as a major building fire, power loss, flood, hurricane, earthquake, human error, and so on. There are so many possible ways that systems can fail, so they need to be designed with the expectation that failure will occur.

Due to such worries being so prevalent, many organisations are investing a large proportion of their budget in solutions that ensure they remain up and running if the worst scenario happens. Whilst it is widely recognised that such measures are needed, there is naturally some discussion and confusion around what solution provides the greatest level of protection.