>> Cassandra process has 63.5 GBÂ virtual size. >> I mention about RES column in top. RES is 8.3G. Very large than 2.5G Used >> Memory Used show in JConsole. > > https://issues.apache.org/jira/browse/CASSANDRA-2868
But note that RSS >= heap size does not imply memory leak, although it is consistent with it. Resident pages will be counted towards the resident size of the process, so that you can see high resident amounts even without memory leaks. (E.g. observe results with https://github.com/scode/alloctest) -- / Peter Schuller (@scode on twitter)