How can I prevent these errors coming? When I created 9 partitions on 3 instances and 2 replication-factor, I didn't have any error. But when I created 36 partitions on 12 instances, I got these errors.
2014-03-07 18:19:28,208] ERROR Controller 9 epoch 12 initiated state change of replica 9 for partition [request_trace,3] from NonExistentReplica to NewReplica failed (state.change.logger) kafka.common.StateChangeFailedException: Replica 9 for partition [request_trace,3] cannot be moved to NewReplicastate as it is being requested to become leader at kafka.controller.ReplicaStateMachine.handleStateChange(ReplicaStateMachine.scala:160) at kafka.controller.ReplicaStateMachine$$anonfun$handleStateChanges$2.apply(ReplicaStateMachine.scala:96) at kafka.controller.ReplicaStateMachine$$anonfun$handleStateChanges$2.apply(ReplicaStateMachine.scala:96) at scala.collection.immutable.HashSet$HashSet1.foreach(HashSet.scala:123) at scala.collection.immutable.HashSet$HashTrieSet.foreach(HashSet.scala:322) at scala.collection.immutable.HashSet$HashTrieSet.foreach(HashSet.scala:322) at kafka.controller.ReplicaStateMachine.handleStateChanges(ReplicaStateMachine.scala:96) at kafka.controller.KafkaController.onNewPartitionCreation(KafkaController.scala:464) at kafka.controller.KafkaController.onNewTopicCreation(KafkaController.scala:452) at kafka.controller.PartitionStateMachine$TopicChangeListener$$anonfun$handleChildChange$1.apply$mcV$sp(PartitionStateMachine.scala:421) at kafka.controller.PartitionStateMachine$TopicChangeListener$$anonfun$handleChildChange$1.apply(PartitionStateMachine.scala:403) at kafka.controller.PartitionStateMachine$TopicChangeListener$$anonfun$handleChildChange$1.apply(PartitionStateMachine.scala:403) at kafka.utils.Utils$.inLock(Utils.scala:538) at kafka.controller.PartitionStateMachine$TopicChangeListener.handleChildChange(PartitionStateMachine.scala:402) at org.I0Itec.zkclient.ZkClient$7.run(ZkClient.java:576) at org.I0Itec.zkclient.ZkEventThread.run(ZkEventThread.java:71)