https://community.cloudera.com/t5/Support-Questions/NiFi-node-keeps-disconnecting-from-the-cluster/m-p/191886#M153965 <A rel="user" href="https://community.cloudera.com/users/1422/xsanderson.html" nodeid="1422" target="_blank">@Xi Sanderson</A><P>The most common reason for not seeing Heartbeats generated on the configured interval is when you have a lot of java full garbage collection (GC) going on. Garbage collection is a stop the world event. The JVM will do nothing else until the garbage collection has completed. Partial garbage collection is normal and healthy and stop the world events here should be extremely short in duration.</P><P>You can look at the GC stats fro your NIFi cluster via the system diagnostics UI. You can get tho this UI via link in the lower right corner of the NiFi summary UI:</P><P><span class="lia-inline-image-display-wrapper lia-image-align-inline" image-alt="15859-screen-shot-2017-05-30-at-105328-am.png" style="width: 1512px;"><img src="https://community.cloudera.com/t5/image/serverpage/image-id/18361iC34D35E76BBDDDF5/image-size/medium?v=v2&amp;px=400" role="button" title="15859-screen-shot-2017-05-30-at-105328-am.png" alt="15859-screen-shot-2017-05-30-at-105328-am.png" /></span></P><P>Young is normal to see, but you want to see hopefully 0 Old Gen events.</P><P>If GC is your issue, you will want to figure out what has changed. New data types or volumes, new dataflows, etc...</P><P>Thanks,</P><P>Matt</P> Sun, 18 Aug 2019 07:18:55 GMT MattWho 2019-08-18T07:18:55Z