Many large IT systems have become too complex to understand. The complexity stems from the ever increasing number of technical parts but also from the increasing number of people involved. Still, the systems are designed, developed, tested, and taken into use without paying enough attention to the issues the inherent system complexity introduces. These issues – called emergent because we are not able to foresee them – result in system failures, downtime, and hasty workarounds and fixes. These, in turn, lead to unsatisfying user experience and unexpected costs.
When dealing with a mission critical information system, failures and downtime are unacceptable. The users need to be able to trust that almost whatever happens, the system is available to the users, in the best possible way. If a mission critical systems is first built, then taken to use, and finally maintained by different organizations, the challenge of divided responsibilities emerges. In the presence of any event regarded as a problem, it is not imminently clear which party is best capable of solving the situation.
The software-as-a-service (SaaS) model is a good fit with mission criticality in a number of ways. When the system is provided as a service by one service provider, there is no doubt who to blame in the occurrence of errors or who should take care of issues raised by the users. At the same time, the SaaS model puts a totally different kind of burden on the shoulders of the company providing the mission critical service. If the service has no option to fail, system design, development, testing, deployment, monitoring and maintenance while being operational, must be done the mission criticality as the first thing in mind.
