Explanation:
The length of the recovery window is defined by business management and determines the acceptable time frame between a disaster and the restoration of critical services/applications. The technical implementation of the disaster recovery (DR) site will be based on this constraint, especially the choice between a hot, warm or cold site. The service delivery objective is supported during the alternate process mode until the normal situation is restored, which is directly related to business needs. The recovery time objective (RTO) is commonly agreed to be the time frame between a disaster and the return to normal operations. It is then longer than the interruption window and is very difficult to estimate in advance. The time frame between the reduced operation mode at the end of the interruption window and the return to normal operations depends on the magnitude of the disaster. Technical disaster recovery solutions alone will not be used for returning to normal operations. Maximum tolerable outage (MTO) is the maximum time acceptable by a company operating in reduced mode before experiencing losses. Theoretically, recovery time objectives (RTOs) equal the interruption window plus the maximum tolerable outage. This will not be the primary factor for the choice of the technical disaster recovery solution.