https://docs.splunk.com/Documentation/Splunk/8.1.1/Updating/Definedeploymentclasses#Ways_to_define_server_classes "When you use forwarder management to create a new server class, it saves the server class definition in a copy of serverclass.conf under $SPLUNK_HOME/etc/system/local. If, instead of using forwarder management, you decide to directly edit serverclass.conf, it is recommended that you create the serverclass.conf file in that same directory, $SPLUNK_HOME/etc/system/local."