I got following exception in Elasticsearch log file:
[2016-04-07 11:26:37,740][WARN ][indices.cluster ] [data-node-vm2] [[mmx_20160210][2]] marking and sending shard failed due to [failed to create shard]
org.elasticsearch.index.shard.IndexShardCreationException: [mmx_20160210][2] failed to create shard
at org.elasticsearch.index.IndexService.createShard(IndexService.java:357)
at org.elasticsearch.indices.cluster.IndicesClusterStateService.applyInitializingShard(IndicesClusterStateService.java:704)
at org.elasticsearch.indices.cluster.IndicesClusterStateService.applyNewOrUpdatedShards(IndicesClusterStateService.java:605)
at org.elasticsearch.indices.cluster.IndicesClusterStateService.clusterChanged(IndicesClusterStateService.java:185)
at org.elasticsearch.cluster.service.InternalClusterService$UpdateTask.run(InternalClusterService.java:480)
at org.elasticsearch.common.util.concurrent.PrioritizedEsThreadPoolExecutor$TieBreakingPrioritizedRunnable.runAndClean(PrioritizedEsThreadPoolExecutor.java:188)
at org.elasticsearch.common.util.concurrent.PrioritizedEsThreadPoolExecutor$TieBreakingPrioritizedRunnable.run(PrioritizedEsThreadPoolExecutor.java:158)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
Caused by: org.apache.lucene.store.LockObtainFailedException: Can't lock shard [mmx_20160210][2], timed out after 5000ms
at org.elasticsearch.env.NodeEnvironment$InternalShardLock.acquire(NodeEnvironment.java:582)
at org.elasticsearch.env.NodeEnvironment.shardLock(NodeEnvironment.java:510)
at org.elasticsearch.index.IndexService.createShard(IndexService.java:310)
What is the possible reason of "failed to create shard" and "can't lock shard, timed out after xxxms"?