1.1 Introduction

For the overall purpose of this book and to better explain the concepts related to Exchange 2000 scalability, this chapter reviews the Exchange 2000 architecture. It identifies the main components and reveals the most critical components used in high-end environments as well as scale-up and scale-out models (many transactions or users per server, and many servers in a single Exchange 2000 organization).

Microsoft Exchange 2000 embodies many features from both Microsoft Exchange 5.5 and Microsoft Commercial Internet Services (MCIS): a solid database engine for messaging and collaboration information, coupled with a scalable and unique way to deal with that information. The last feature is implemented through the Exchange Installable File System in Exchange 2000, a quite new way for clients and protocol servers to deal with the storage databases.

Microsoft Exchange, as a product family, has evolved by proposing a client/server-based model (at a time when File Share messaging systems were deployed, such as cc:Mail or MS-Mail), to a fully scalable high-end platform for enterprise and Internet messaging and collaboration as it is today. In fact, Microsoft Exchange becomes a growing, important source of information in an enterprise, and may very well feed rich applications, with information and processes, such as workflow processes.

When Microsoft Exchange 4.0 was released in the first quarter of 1996, the messaging market was vastly disparate, ranging from File Sharing solutions such as MS-Mail, cc:Mail, or GroupWise, to true enterprise-level but niche client/server messaging systems, such as Digital's ALL-IN-1 product. This initial release...