title: Cannot create index in mongodb, "key too large to index"
body: <p>I am creating  index in mongodb having 10 million records but following error</p>
  
  <pre><code>db.logcollection.ensureIndex({"Module":1})
  {
          "createdCollectionAutomatically" : false,
          "numIndexesBefore" : 3,
          "ok" : 0,
          "errmsg" : "Btree::insert: key too large to index, failing play.logcollection.$Module_1 1100 { : \"RezGainUISystem.Net.WebException: The request was aborted: The request was canceled.\r\n   at System.Net.ConnectStream.InternalWrite(Boolean async, Byte...\" }",
          "code" : 17282
  }
  </code></pre>
  
  <p>Please help me how to  createindex in mongodb,</p>