Each day your server is running it is capturing log files. In your [install-dir]/logs directory, you will see an appended log file named wowzastreamingengine_access.log and the daily access logs that look like this: wowzastreamingengine_access.log.2015-02-20. So based on your example, you should notice a new file created each day with a start time of 00:00:00. This is by design. The same goes for the error log files as well. If you restart the server, it is entered into the log file for that day.