I'm studying for the CCSP exam and one of the BC/DR terms that is referenced in my study material is "Maximum Allowable Downtime". The definition for it is:

MAD (Maxium Allowable Downtime) How long it would take for an interruption in service to kill an organization, measured in time. For instance, if a company would fail because it had to halt operations for a week, then its MAD is one week.

The study material book I'm reviewing actually didn't mentioned MTD anywhere but my understanding from other resources is that Maximum Tolerable Downtime refers to the amount of time that can pass before an "event" can reasonably be considered an impactful "disaster" (of course with the understanding that exceptions occur)

The definition of MAD above though, sounds way more... permanent/absolute and far worse than a disaster.

So, is MTD and MAD the same thing? Is this just the author writing it in a creative way? Or are there distinct/notable differences between Maximum Tolerable Downtime and Maximum Allowed Downtime?

  • 1
    „To kill an Organisation“ sounds not like a well defined definition. And so are the concepts. Why would x days be tolerable but x+1 day not?
    – eckes
    Commented Jun 1, 2018 at 14:14
  • 2
    @eckes Agreed. Ironically, this is straight out of the "official" study guide for the exam. :-(
    – Mike B
    Commented Jun 1, 2018 at 14:20

1 Answer 1


They are not the same thing. MTD is the time allowed before the entire business becomes at risk (e.g. the company may go out of business), whereas MAD is the time at which an actual business impact occurs (which may or may not be crippling - it could just be painful). MTD is "how long before it puts us of business," MAD is "this did hurt us directly or indirectly an undetermined amount."

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .