Before you begin reviewing the available technologies that support disaster recovery, you firstmust consider the business. You need to identify which business processes are mostimportant to keeping your business operational.

Once you have identified the most critical business processes, work with the business units to determine their availability requirements for each process. Document the requirements in an internal SLA that specifies the availability goals for each process and articulates the costs of not meeting the goals.

Documenting the cost of not meeting availability requirements helps you determine the value of a software investment used to improve availability. This information also helps you prioritize the processes to analyze. After documenting the service levels required, you can start analyzing the availability needs of each business process technology by technology.

Most organizations define "availability" somewhere along a continuum between multiple hours of downtime with significant data loss to real-time 24/7 uptime with zero data loss. Your definition depends on your business needs, your data and application requirements and your organizational structure. The goal, however, should be to prevent the inevitable system downtime from affecting business uptime.