The goal of high availability is to produce a system that lets an IT department minimize downtime on critical systems. In other words, high availability is about putting in place the people, processes, and technologies that allow for rapid rebuilding of a failed component while incurring the least amount of outage. You measure availability with respect to downtime.
Disaster recovery is a buzzword that's currently out of favor with IT executives and business decision makers. But the goal of disaster recovery is also to put in place people, processes, and technologies that let you rapidly rebuild a failed component while incurring the least amount of outage. In IT, disaster recovery is seen as a cost that drains IT budgets with long, complicated processes, but high availability is recognized as essential to the company's profit stream. That's unfortunate, because the words are interchangeable when you're talking about keeping systems up and running.
For IT professionals who wish they had the budget to implement robust disaster-recovery plans, the solution is easy—package disaster recovery as high availability. IT executives reading this article need to understand that you can leverage every investment you make in disaster recovery into high availability, and vice versa. No matter which term you use, you're trying to accomplish the same goal: making data available to users 100 percent of the time.