7.1 High Availability Is A Key Concern

Organizations deploying messaging and collaboration applications face many challenges. Very often, implementers focus on performanceand scalability. Questions such as "How many users per server can I deploy?" or "How do we do performance monitoring and tuning?" are among those most often heard. Equally important are the administrative and management aspects of deployment. Issues such as user administration, directory synchronization, database maintenance, and server management are common concerns. But it is disaster recovery and high availability that are at the forefront of the minds of implementers of Microsoft Exchange Server. Due to the mission-critical nature of messaging and collaborative applications, minimizing downtime and providing for rapid recovery are paramount. With the increasing size of information stores combined with the limits of current backup and restore technologies, disaster recovery issues can be the limiting factor when deciding the number of users per server to deploy. With tolerance for downtime low, keeping an Exchange Server constantly available is a key concern for IT organizations. The issue of high availability is a most important issue for Exchange Server deployments. When many look to increase availability and reliability for Exchange Server, cluster technology immediately comes to mind.

In this chapter, I will try to avoid an in-depth focus on clustering technology itself. My focus will be mostly on support and implementation of clustering in Exchange 5.5 Enterprise Edition and Exchange 2000 Enterprise Server. Since this book is geared toward Exchange 2000, I will spend the majority of my...