2.1 Why would you want to scale?

Scalability is the ability for a system or a group of systems to grow in processing and storage capability without architectural modifications. In the Microsoft Exchange environment, scalability has always been a concern to address to cope with the rising use of electronic messaging in commercial or corporate environments.

Today, commercial environments include wireless messaging services or pure Internet messaging services that require the capability to cope with the peak load of activity while at the same time remaining manageable. In corporate environments, scalability needs to be addressed mostly in terms of constantly growing information to store, manage, transmit, and retrieve efficiently.

The basic idea of scalability is to architect solutions that don't require fundamental changes as the transaction load or, put more simply, the user activity ramps up and increases across time. This ramp-up can be very steep in commercial environments (Internet Service Provider or Application Service Provider), more than in enterprise environments. The goal is being able to deal with activity ramp-up in a proactive manner so that users don't have to suffer from sluggish server performance if and when they can actually connect to the server.

Microsoft Exchange 2000 comes with great scalability features, and in this chapter we discuss the areas of the product that have improved the most compared with Microsoft Exchange 5.5. However, it is necessary to guard against not trying to exceed get too rapidly Microsoft Exchange's scalability boundaries and to learn how to properly address them.

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