Evaluating Usage

You can predict how actions will affect server load by considering aggregates over time. For example, you can evaluate all the user's actions (such as sending or reading messages and other activities) and all the background actions of the server on his or her behalf during a certain time period (such as an eight-hour workday). This can help you classify the user's activity level in comparison to others. Estimate how many actions a user performs over time, the load those actions place on the server, and then make rough performance predictions based on an "average" user.

To determine how many users a server can support, then, you need to determine the patterns of the users in your organization. For example, you can classify the users in your organization according to low, medium, and heavy usage, based on daily averages.

Type of usage	User Pattern
Low	Sends 3 messages. Reads new mail 5 times and old mail 12 times. Makes 1 change to his or her schedule.
Medium	Sends 6 messages. Reads new mail 15 times and old mail 12 times. Makes 5 changes to his or her schedule.
Heavy	Sends 8 messages. Reads new mail 20 times and old mail 12 times. Makes 10 changes to his or her schedule.

You can also use the Microsoft Exchange Server Load Simulator (Loadsim.exe) tool to help you determine the level of performance that's acceptable for your organization's users. Load Simulator can help you determine how many users your Microsoft Exchange Server computer can support. It is designed to provide a realistic load on a Microsoft Exchange Server computer by simulating the behavior or users on one or more Microsoft Outlook computers. For more information on running the Load Simulator tool, see the Microsoft Exchange Server Resource Guide.