title: Cassandra cluster: could not reach linear scalability
body: <p>I've configured a simple cluster using two PC with identical spec:</p>
  
  <pre><code>  cpu core i5
     RAM: 8GB ddr3
     Disk: 1TB 5400rpm
     Network: 1 G (I've test it with iperf, it really is!)
  </code></pre>
  
  <p>using the common configs described in many sites including datastax itself: </p>
  
  <pre><code>cluster_name: 'MyCassandraCluster'
  num_tokens: 256
  seed_provider:
    - class_name: org.apache.cassandra.locator.SimpleSeedProvider
      parameters:
           - seeds: "192.168.1.1,192.168.1.2"
  listen_address:
  rpc_address: 0.0.0.0
  endpoint_snitch: GossipingPropertyFileSnitch
  </code></pre>
  
  <p>Running stress tool:</p>
  
  <pre><code>cassandra-stress write n=1000000 -rate threads=1000 -mode native cql3 -node 192.168.1.1,192.168.1.2
  </code></pre>
  
  <p>Over each node it shows 39 K writes/seconds, but running the same stress tool command on cluster of both nodes shows 45 K writes/seconds. I've done all the tuning mentioned by apache and datastax.
  There are many use cases on the net proving Cassandra linear Scalability So what is wrong with my cluster?</p>