title: Apache Nifi slow cluster issue
body: <p>I am using a Apache nifi for one of my clickstream projects to do some ETL.</p>
  
  <p>I am getting traffic around <strong>300 messages per second</strong> currently with the following infra:</p>
  
  <ul>
  <li>RAM - 16 GB</li>
  <li>Swap - 6 GB</li>
  <li>CPU - 16 cores</li>
  <li>Disk - 100GB (Persistance not required)</li>
  <li>Cluster - 6 nodes</li>
  </ul>
  
  <p>The entire cluster UI has become extremely slow with the following issues</p>
  
  <ul>
  <li>Processors giving back pressure when some failure happens, which consumes lot of threads</li>
  <li>Provenance writing becomes very slow</li>
  <li>Heartbeat across nodes becomes slow
  <a href="https://i.stack.imgur.com/j2hmk.png" rel="nofollow noreferrer">Cluster Heart beat</a></li>
  </ul>
  
  <p>I have the following questions on the setup </p>
  
  <ul>
  <li>Is RPG use recommended, as it is a HTTP call, which i using to spread
  across all the nodes, as there is an existing issue with EMQTT
  process for consumer group.</li>
  <li>What is the recommended value of thread count that should be allotted
  per core?</li>
  <li>What are the guidelines for infrastructure sizing </li>
  <li>What are the tuning parameters for a large cluster with high incoming requests and lot of heavy JSON parsing for transformation</li>
  </ul>