title: How to Split solr shard in solr cloud
body: <p>I am using solr 4.10.3 in solrCloud mode. I have one shard and 3 replica. external zookeeper ensemble in being used. My document in one index has been increase too much. Now I want to create more shards. I tries to use </p>
  
  <pre><code>http://localhost:8983/solr/admin/collections?action=SPLITSHARD&amp;collection=collection1&amp;shard=shard1
  </code></pre>
  
  <p>But it gives following error</p>
  
  <pre><code>Error executing split operation for collection: collection1 parent shard: shard1
  java.lang.NullPointerException
      at org.apache.solr.cloud.OverseerCollectionProcessor.splitShard(OverseerCollectionProcessor.java:1288)
      at org.apache.solr.cloud.OverseerCollectionProcessor.processMessage(OverseerCollectionProcessor.java:563)
      at org.apache.solr.cloud.OverseerCollectionProcessor$Runner.run(OverseerCollectionProcessor.java:2629)
      at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
      at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
      at java.lang.Thread.run(Thread.java:745)
  Collection: collection1 operation: splitshard failed:org.apache.solr.common.SolrException
      at org.apache.solr.cloud.OverseerCollectionProcessor.splitShard(OverseerCollectionProcessor.java:1569)
      at org.apache.solr.cloud.OverseerCollectionProcessor.processMessage(OverseerCollectionProcessor.java:563)
      at org.apache.solr.cloud.OverseerCollectionProcessor$Runner.run(OverseerCollectionProcessor.java:2629)
      at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
      at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
      at java.lang.Thread.run(Thread.java:745)
  Caused by: java.lang.NullPointerException
      at org.apache.solr.cloud.OverseerCollectionProcessor.splitShard(OverseerCollectionProcessor.java:1288)
  null:org.apache.solr.common.SolrException
  null:org.apache.solr.common.SolrException
      at org.apache.solr.handler.admin.CollectionsHandler.handleResponse(CollectionsHandler.java:364)
      at org.apache.solr.handler.admin.CollectionsHandler.handleSplitShardAction(CollectionsHandler.java:606)
      at org.apache.solr.handler.admin.CollectionsHandler.handleRequestBody(CollectionsHandler.java:172)
      at org.apache.solr.handler.RequestHandlerBase.handleRequest(RequestHandlerBase.java:135)
  </code></pre>
  
  <p>Where is the problem and what is its soultion?</p>