Cisco Systems OL-24201-01 Global and Per-Instance Logging Categories, Log Message Severity Levels

Chapter 19 Understanding Logging

About Logging

Each log message contains the following information:

•Event code—A unique message code.

•Logging category—Identifies the category to which a log message belongs.

•Severity level—Identifies the level of severity for diagnostics. See Log Message Severity Levels, page 19-4for more information.

•Message class—Identifies groups of messages of similar context, for example, RADIUS, policy, or EAP-related context.

•Message text—Brief English language explanatory text.

•Description—English language text that describes log message reasons, troubleshooting information (if applicable), and external links for more information.

•Failure reason (optional)—Indicates whether a log message is associated with a failure reason. Passwords are not logged, encrypted or not.

Global and Per-Instance Logging Categories

By default, a single log category configuration applies to all servers in a deployment. For each log category, the threshold severity of messages to be logged, whether messages are to be logged to the local target, and the remote syslog targets to which the messages are to be sent to, are defined.

The log categories are organized in a hierarchical structure so that any configuration changes you make to a parent category are applied to all the child categories. However, the administrator can apply different configurations to the individual servers in a deployment.

For example, you can apply more intensive diagnostic logging on one server in the deployment. The per-instance logging category configuration displays all servers in a deployment and indicates whether they are configured to utilize the global logging configuration or have their own custom configuration.

To define a custom configuration for a server, you must first select the Override option, and then configure the specific log category definitions for that server.

You can use the Log Message Catalog to display all possible log messages that can be generated, each with its corresponding category and severity. This information can be useful when configuring the logging category definitions.

Log Message Severity Levels

You can configure logs of a certain severity level, and higher, to be logged for a specific logging category and add this as a configuration element to further limit or expand the number of messages that you want to save, view, and export.

For example, if you configure logs of severity level WARNING to be logged for a specific logging category, log messages for that logging category of severity level WARNING and those of a higher priority levels (ERROR and FATAL) are sent to any configured locations. Table 19-1describes the severity levels and their associated priority levels.

	User Guide for Cisco Secure Access Control System 5.3
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