You've mentioned the RAM of the machine your DataNode is assigned to run on, however what is your configured DataNode Java JVM heap size? You could try raising it by 1 GB from its current value, to resolve this. Also, what's the entire Out of Memory message, 'cause "unable to create a new native thread" (or summat) is entirely different than "Java heap space" in what it implies (nproc limit issue vs. actual heap memory exhaustion). ... View more