What does the Maximum Tolerable Downtime (MTD) determine?

According to the CISSP For Dummies1, the Maximum Tolerable Downtime (MTD) determines the estimated period of time a business can remain interrupted beyond which it risks never recovering. This means that the MTD is the maximum acceptable duration of a disruption that the organization can tolerate before it suffers unacceptable consequences, such as loss of revenue, reputation, or customers. The MTD is an important input for the business continuity planning and disaster recovery planning processes, as it helps to define the recovery objectives and strategies for each business process and function. The MTD is not the same as the estimated period of time a business critical database can remain down before customers are affected, the fixed length of time a company can endure a disaster without any DR planning, or the fixed length of time in a DR process before redundant systems are engaged, as these are different concepts that may or may not be related to the MTD. References: 1