By default, Ambari is giving "Druid Historical" component -XX:MaxDirectMemorySize=1048576m
I'm asking the Druid devs what a good default is, but 1TB of RAM is definitely too much! Once I get an answer, can send a pull request over.
`-XX:MaxDirectMemorySize` comes from druid-env. druid.historical.jvm.direct.memory and is appended with ‘m’:
The default value is ‘1048576` which, when appeneded with 'm', is 1TB!:
In the JVM config file which Ambari manages: