Typical Types of Log Messages 

Log messages can generally be divided into the following types:

·        Error messages

If the processing of an application cannot proceed and corrective action needs to be taken, a log message describing the problem (and if possible also the solution) must be issued.

The severity level of such a message depends on the severity of the error: If the application is still usable for other requests, the severity level has to be Error, whereas it must be Fatal, if the application is not useable anymore.

·        Event notifications

If there are occasions in the software or hardware components, which carry probably important information for the addressees, but which do not need immediate (or possibly none at all) corrective action, this is called “event notification”. Examples are information for security audits (a user has been locked due to too many logon attempts with an incorrect password), the information about a nearly full file system or the reconfiguration of a software component (for example, a buffer) with a different size.

The severity levels of such messages must depend on the required action to solve the problem: If there is a possibility that corrective action needs to be taken, then the severity level must be Warning, whereas if normally no corrective action is necessary, the severity level has to be Info.

·        Status recording

With status recording one typically indicates two different types of status:

Ў        Startup and shutdown of software or hardware components

Ў        Information about the progress of an application (for example, the amount of documents processed in conjunction with the amount of resources used).

In both cases the severity level of these message types must be Info.

·        Context information

If additional information needs to be provided (for example, in conjunction with error log messages) to be able to solve problems, this is called  “context information”.

The severity level of this message must be Info.