I had too much trouble today trying to minimise selenium driver logs, only to find out you only need to pass environment option upon starting selenium just like below. Just sharing this one for others sake. :)
# Log levels are the following to choose from: OFF, SEVERE, WARNING, INFO, DEBUG, FINE, FINER, FINEST, ALL
java -jar -Dselenium.LOGGER.level=WARNING /opt/selenium/selenium-server-standalone.jar
You can also set log file like:
java -jar -Dselenium.LOGGER=/tmp/my_file.log /opt/selenium/selenium-server-standalone.jar
You can do more experiments if needed. Play around. Enjoy!