Messages are included in log files or filtered out of log files according to the severity of the message, the category of the message, and the log-level that has been configured for that category. The categories and log-levels for the error logs and access logs are different, and are discussed in the sections that follow.
Messages are ranked according to their severity. Messages can have one of the following severities, where error is highest severity and debug is the lowest severity:
Messages with a severity that is lower than the log-level configured for its message category are not included in the log file. Messages with a severity that is equal to or higher than the log-level configured for its associated message category are included in the log file.