Defining the recovery time objectives (RTO) for your activities is one of the most critical things the business continuity manager will carry out. Get them wrong and the whole basis for your recovery strategy is flawed.
Many times organizations conduct traditional disaster recovery exercises where testing is done in silos and the scope is limited and restricted only to host level recovery of individual systems. With growing technology changes and globalization trends, the intricacy and interdependencies of applications have become more complex in recent years and major applications are spread across multiple locations and multiple servers.
The smartest way to think about disaster is in terms of when, not if. The object of the game is to mitigate risk as much as is feasible, hope for the best, and prepare for the worst.