title: Why swapping is not a good idea in zookeeper and kafka?
body: <p>I have read instructions on</p>
  
  <pre><code>do not use swap
  </code></pre>
  
  <p>both on zookeeper and kafka. I know that kafka depends on the pagecaching to keep parts of sequential logs cached in-memory even they are written to disk.</p>
  
  <p>But can not understand how swapping can harm zk and kafka.</p>