가이드에는 힙사이즈를 전체 물리 메모리의 50%로 셋팅하는것으로 권장. 32기가라면 16기가정도로 셋팅. Set Xms and Xmx to no more than 50% of your total memory. Elasticsearch requires memory for purposes other than the JVM heap. For example, Elasticsearch uses off-heap buffers for efficient network communication and relies on the operating system’s filesystem cache for efficient access to files. The JVM itself also requires some memory. I..