By default, OpenDJ installs with options appropriate for evaluation, not for production. JavaSettings You can change JVM options for the server in the QuickStart installer, and alternatively using the Control Panel (Runtime Options > Java Settings), or with the dsjavaproperties command after editing the config/java.properties file. Heap size The JVM heap size by default is either 256 MB or 1 GB. In production, use at least a 2 GB heap (-Xms2G -Xmx2G). Server optimizations Use -server to select the HotSpot Server VM. 32-bit vs. 64-bit For heap sizes over 4 GB on 64-bit systems use -d64. Garbage collection Use -XX:+UseConcMarkSweepGC to select the CMS garbage collector for low GC pause times. New generation size If your directory handles high throughput, set the new generation size large enough for the JVM to avoid promoting short-lived objects into the old gen space (-XX:NewSize=512M).