The imq.log.file.dirpath and imq.log.file.filename broker properties identify the log file to use and the imq.log.console.stream property specifies whether console output is directed to stdout or stderr.
The imq.log.level property controls the categories of metric information that the Logger gathers: ERROR, WARNING, or INFO. Each level includes those above it, so if you specify, for example, WARNING as the logging level, error messages will be logged as well.
The imq.log.console.output and imq.log.file.output properties control which of the specified categories the Logger writes to the console and the log file, respectively. In this case, however, the categories do not include those above them; so if you want, for instance, both errors and warnings written to the log file and informational messages to the console, you must explicitly set imq.log.file.output to ERROR|WARNING and imq.log.console.output to INFO.
In the case of a log file, you can specify the point at which the file is closed and output is rolled over to a new file. Once the log file reaches a specified size (imq.log.file.rolloverbytes) or age (imq.log.file.rolloversecs), it is saved and a new log file created.
See Monitoring Properties for additional broker properties related to logging and subsequent sections for details about how to configure the Logger and how to use it to obtain performance information.