Why This Chapter Matters

Messaging systems are often a "mission critical" network service within an organization. Therefore, minimizing the downtime of the e-mail servers is one of the top priorities of a network administrator. For companies that require the ultimate in performance and reliability, Exchange Server 2003 supports being installed on network load balanced and clustered servers, which use redundant hardware resources to ensure that there is not a single point of failure and that the applications that run on them have as close to 100 percent uptime as possible. Another performance-maximizing benefit of Exchange Server 2003 is that it supports front-end and back-end architecture, which was introduced in Chapter 3, "Configuring a Microsoft Exchange Server 2003 Infrastructure."

This chapter focuses on Exchange Server organizations designed to support thousands of users with a server architecture that is more advanced than has been previously discussed. It is important to be just as comfortable working with Exchange Server 2003 in an enterprise clustered environment supporting thousands of users as in a small single-server environment supporting a few dozen users.