title: Poor performance in MongoDB sharding
body: <p>I am new with MongoDB sharding, and we are facing performance issues. I tried with many test cases with three servers and I feel MongoDB sharding does not give better performance compare to single instance of mongod on a single server.</p>
  
  <p>Am I correct? If I am not correct then kindly provide test collection, shard key, and load test procedure.</p>
  
  <p>Test case 1:</p>
  
  <p>I did one load test between single instance on a mongod and single shard (<a href="http://docs.mongodb.org/manual/core/sharded-cluster-architectures-test/" rel="nofollow">http://docs.mongodb.org/manual/core/sharded-cluster-architectures-test/</a>) and I observed 40% performance degradation in sharding setup because of mongos and config server.</p>
  
  <p>Does mongos and config server take 40% server resources?</p>
  
  <p>Test case 2:</p>
  
  <p>We observed 10K TPS on single instance of mongod instance. We observed 5.1K TPS in mongo shard on three servers with same capacity hardware (we used same server for single mongod instance test). We used shard key as hashed index ObjectId.</p>
  
  <p>Why we could not get 10K+ performance with three servers? Is there any way to get 10K + performance using sharding? If yes then how?</p>