title: How can I view the progress of long-running Cassandra operations?
body: <p>Several operations in Cassandra seem to take a long time to complete, and I'm trying to determine ways to get insight into their progress, or determine if the system has stalled.</p>
  
  <p>The two I'm specifically interested in are:</p>
  
  <ul>
  <li><code>nodetool decommission</code></li>
  <li><code>nodetool repair</code></li>
  </ul>
  
  <p><a href="http://mail-archives.apache.org/mod_mbox/cassandra-user/201108.mbox/%3C4CDCDAB3-6E52-4182-B033-E5B1DDBCA114@thelastpickle.com%3E">This</a> seems to suggest that you can use <code>nodetool compactionstats</code> to view the progress of <code>nodetool repair</code>, but <code>nodetool compactionstats</code> doesn't output anything that I can derive progress from. Compaction jobs come and go, but the number of pending jobs seems to hover around 40. There's also a timer at the bottom, and it <em>appears</em> to be going down, but it is going down very slowly. (<s>I'd say it's going down by about 3 minutes every 10 minutes?</s> It just quadrupled.)</p>
  
  <p>A chat-room suggested I use <code>nodetool netstats</code> to "view the streams" for decommission, but again, this just show me that some "streams" are occurring, and how complete they are. Most are listed as 100% (or more, in some cases!), and occasionally, they all are, but a new stream will come along, so I'm in the dark as to how this conveys progress of a decom.</p>