I don´t like the output of the com.sun.enterprise.server.logging.UniformLogFormatter which might be uniform but not very helpful. So in a first step I just repl
com.sun.enterprise.server.logging.UniformLogFormatter
Have a look at Configuring format of server log on the GlassFish forums. Basically, you need to:
domain_dir/lib/ext
<mydomain>/config/logging.properties