title: MongoDB Sharding Policy
body: <p>I am trying to understand the following behavior displayed by my sharding setup. The data seems to only increase on a single shard as I continuously add data. How does MongoDB shard or distribute data across different servers? Am I doing this correctly? MongoDB version 2.4.1 used here on OS X 10.5.</p>
  
  <p><img src="https://i.stack.imgur.com/spzKV.jpg" alt="enter image description here"></p>
  
  <p>As requested, sh.status() as follows:</p>
  
  <pre><code>mongos&gt; sh.status()
  sharding version: {
      "_id" : 1,
      "version" : 3,
      "minCompatibleVersion" : 3,
      "currentVersion" : 4,
      "clusterId" : ObjectId("52787cc2c10fcbb58607b07f") }
  shards:
      {  "_id" : "shard0000",  "host" : "xx.xx.xx.xxx:xxxxx" }
      {  "_id" : "shard0001",  "host" : "xx.xx.xx.xxx:xxxxx" }
      {  "_id" : "shard0002",  "host" : "xx.xx.xx.xxx:xxxxx" }
   databases:
      {  "_id" : "admin",  "partitioned" : false,  "primary" : "config" }
      {  "_id" : "newdb",  "partitioned" : true,  "primary" : "shard0001" }
              newdb.prov
                      shard key: { "_id" : 1, "jobID" : 1, "user" : 1 }
                      chunks:
                              shard0000       43
                              shard0001       50
                              shard0002       43
  </code></pre>