title: Cassandra: read/s write/s
body: <p>I'm trying to figure out the throughput of my Cassandra cluster, and can't figure out how to use nodetool to accomplish that. Below is a sample output:</p>
  
  <pre><code>Starting NodeTool
  Keyspace: realtimetrader
  Read Count: 0
  Read Latency: NaN ms.
  Write Count: 402
  Write Latency: 0.09648756218905473 ms.
  Pending Flushes: 0
          Table: currencies
          SSTable count: 1
          Space used (live): 5254
          Space used (total): 5254
          Space used by snapshots (total): 0
          Off heap memory used (total): 40
          SSTable Compression Ratio: 0.0
          Number of keys (estimate): 14
          Memtable cell count: 1608
          Memtable data size: 567
          Memtable off heap memory used: 0
          Memtable switch count: 0
          Local read count: 0
          Local read latency: NaN ms
          Local write count: 402
          Local write latency: 0.106 ms
          Pending flushes: 0
          Bloom filter false positives: 0
          Bloom filter false ratio: 0,00000
          Bloom filter space used: 24
          Bloom filter off heap memory used: 16
          Index summary off heap memory used: 16
          Compression metadata off heap memory used: 8
          Compacted partition minimum bytes: 125
          Compacted partition maximum bytes: 149
          Compacted partition mean bytes: 149
          Average live cells per slice (last five minutes): 0.0
          Maximum live cells per slice (last five minutes): 0
          Average tombstones per slice (last five minutes): 0.0
          Maximum tombstones per slice (last five minutes): 0
  </code></pre>
  
  <p>I run the command:</p>
  
  <pre><code>nodetool cfstats
  </code></pre>
  
  <p>to get this, and then subtract the latter, "Local read count:" from the earlier one. 
  But I'm not sure what the "Local" here means?
  Does it mean its local to that node and in a ring of 5 nodes, I should multiple the value by 5? Or is it that the simple subtraction will give me the correct result?</p>
  
  <p>Also, which JMX bean should I be looking at to get these #'s?</p>