Andy Mallon takes us through the notion of downtime:
There’s a lot of discussion about preventing downtime. As a DBA and IT professional, it’s my sworn duty to prevent downtime. I usually describe my job as DBA something along the lines of, “to make sure data is always available to the people and applications that need it, and never available to the people and applications that shouldn’t have it.” Preventing downtime is certainly important for that first part–but how the heck do you define downtime?
Andy asks more questions than provides answers, but these are the types of questions which the technical side and the business side can get together on to define what constitutes downtime.