Diagnostics Logging Categories

Diagnostics logging levels are set by category. A category is a group of related functions. Each category of Microsoft Exchange Server service has a diagnostics logging level. When a service generates an event with a significance number less than or equal to the logging level, the event is recorded in the event log. If the significance number of the event is greater than the logging level, it is ignored.

Events can be logged from every category of every service on every server. However, during routine operation, to limit the amount of information that accumulates, you should set diagnostics logging to None for every category of every service on every server. At this level, only error events and critical error messages are written to the log. The logging level set for a component of a server applies only to that component. It does not affect levels set for other components of the same server or like components on other servers.

You can start diagnostics logging if you need to troubleshoot a problem. When you increase a logging level, be selective. Increase levels on only those aspects of the service that might be related to the problem. Setting a level too high can produce a log filled with events that are irrelevant to your investigation.

Understanding the Diagnostics Logging Property Page

The Diagnostics Logging property pages are similar for all components and connectors, except for the Microsoft Schedule+ Free/Busy Connector, which is described separately. This property page shows the application name of the service, a list of diagnostic categories, and the current logging level for each category.

The columns correspond roughly to the structure of Event Viewer. The application name in the Service column in the Diagnostics Logging property page appears in the Source box of the application event log. Also, the categories appear in the Category box of the application event log.

Option	Description
Services	The service name.
Category	A group of related application functions. Logging levels are set by category.
Logging level	The current logging level for the category.

Changing the Diagnostics Logging Level

The logging level determines which events are written to the Windows NT application event log. When Microsoft Exchange Server generates an event less than or equal to the logging level, the event is logged.

1. Select the Diagnostics Logging tab.
2. Select a category.
3. Choose a logging level.

Option	Description
None	Logs only critical events and error events. This is the default and should be changed only if a problem occurs.
Minimum	Logs high-level events in the event log. These might include one message for each major task performed by the service. Use this setting to begin an investigation when the location of the problem is unknown.
Medium	Messages are sent to the event log to record steps taken to run a task. This provides more information than the minimum level but not the detail of the maximum level. Use this when the problem has been narrowed to a service or group of categories.
Maximum	Provides a complete trail of the operation of the service; messages can be sent for each line of code in the service. Use this level when the problem has been traced to a particular category or a small set of categories. This level logs all events. This can log a large amount of information, which can affect server performance.