# System Properties

Properties files let you configure the global behavior of Meridian. Configuration can also affect the Java virtual machine under which Meridian runs. You must restart Meridian for changes to take effect. Access the configuration files in `${OPENNMS_HOME}/etc`. The priority for Java system properties is as follows: 1. Those set via the Java command line (for example, in `opennms.conf` via `ADDITIONAL_MANAGER_OPTIONS`). 2. `opennms.properties.d/*.properties` Files in this directory are loaded alphabetically. 3. `opennms.properties` 4. `libraries.properties` 5. `rrd-configuration.properties` 6. `bootstrap.properties`  To avoid conflicts with customized configurations, you can add all custom properties to one or more files in `${OPENNMS_HOME}/etc/opennms.properties.d/`. We recommend that you do not modify default OpenNMS properties. Instead, create dedicated files with your customized properties in `opennms.properties.d/`.