In my elasticsearch cluster of 3 nodes, following is the memory usage as reported by _cat/nodes/ : -
and following is the memory usage of elasticsearch process as checked by "top" : -
es01 : - VIRT : 217 g, RES : 34g , SHR : 2.0g
Total memory usage of system :- Mem: 62.867G total, 61.625G used, 10.784G cached ,538.797M buffers
It is similar for all the 3 systems, resident memory in use by elasticsearch is about 34 gb, i am using a max heap size limit of 30 gb.
Overall memory usage of systems is close to what is showed by ram.current, so does it show the memory usage of the system es is running on? or the memory usage of es process?
Seems like the first to me, however https://www.elastic.co/guide/en/elasticsearch/reference/current/cat-nodes.html "Used total memory" which is not clear.