title: Are Cassandra JMX metric(Stages and Operations) cluster-wide or local?
body: <p>In Cassandra JMX metrics, 
  below few categories show something weird pattern.</p>
  
  <pre><code>  "org.apache.cassandra.request:type=MutationStage", "CompletedTasks"
    "org.apache.cassandra.request:type=ReadRepairStage", "CompletedTasks"
    "org.apache.cassandra.request:type=ReadStage", "CompletedTasks"
    "org.apache.cassandra.request:type=ReplicateOnWriteStage", "CompletedTasks"
    "org.apache.cassandra.request:type=RequestResponseStage", "CompletedTasks"
  
    "org.apache.cassandra.db:type=StorageProxy", "ReadOperations"
    "org.apache.cassandra.db:type=StorageProxy", "WriteOperations"
  </code></pre>
  
  <p>I thought these metrics are not cluster-side (i.e. accumulated node locally, not total nodes' sum).
  But, Referring the JMX Metrics graph(home-made monitoring), these metrics are summed of total node's activities.</p>
  
  <p><img src="https://i.stack.imgur.com/GE2ru.png" alt="Cassandra Stage&#39;s CompletedTasks Chart">
  The cluster monitored have 10 cassandra nodes.
  And you can see that all node's completed stage counter have same value.</p>
  
  <p>Does above jmx metric present all cassandra nodes' total activities ?</p>
  
  <p>Thanks.</p>