Log levels for the service director are set differently than log levels for the service controller, Platform Management Console, and web service gateway. Logged by the BIND DNS server, the service director logs information gathered during the updating and querying of service instance location.
The default log level for the service director is set to severity debug 3. If your system is running well, you likely want to set the severity to something lower. Only use severity debug [level], which generates a lot of messages, for troubleshooting or debugging purposes. In this case, you may wish to reduce the associated log class as well.