As I charge down the path of building a mission-critical Exchange deployment, it would not be prudent to start without a discussion and investigation into downtime and outages for Exchange Server. If your messaging system has become mission critical, the cost of downtime can be devastating to an organization. These costs can come in the form of lost revenue, lost opportunity, failed Service-Level Agreements (SLAs), and/or noncompliance/performance penalties. This does not even consider the fixed costs that an organization must pay whether its employees are working or not (nor does it account for those who just hang it up for the day because their server is down). What can be the most damaging are the incalculable losses such as the loss of customer relationships or satisfaction. When your customers and business partners are affected by an outage in your messaging system, they may perceive a poorly run organization with which they are not excited to do business. As a result, our discussions around outage and downtime should begin in the business context. In other words, what does downtime of your Exchange deployment really cost the company? The higher the quantifiable costs, the more dollars are justified for deploying high-availability measures and investing in personnel and procedures in order to reduce downtime. The more successful an organization is in delivering the levels of reliability required, the faster a return on investment can be realized. In this chapter, we will look at the enemy of mission-critical systems downtime. It is important that we...