Hadoop 2.1.0 gap in log error

[Giri M]

I am testing Hadoop 2.1.0 and planning to migrate my existing Hadoop 1 to Hadoop 2.1.0. But during testing I encountered the following error, when I started the namenodes after shuting the cluster down. I couldn't recreate the problem. Please share possible reasons for the error.

2013-09-26 10:44:41,914 FATAL org.apache.hadoop.hdfs.server.namenode.ha.EditLogTailer: Unknown error encountered while tailing edits. Shutting down standby NN.

java.io.IOException: There appears to be a gap in the edit log.  We expected txid 26, but got txid 5400.

at org.apache.hadoop.hdfs.server.namenode.MetaRecoveryContext.editLogLoaderPrompt(MetaRecoveryContext.java:94)

at org.apache.hadoop.hdfs.server.namenode.FSEditLogLoader.loadEditRecords(FSEditLogLoader.java:183)

at org.apache.hadoop.hdfs.server.namenode.FSEditLogLoader.loadFSEdits(FSEditLogLoader.java:111)

at org.apache.hadoop.hdfs.server.namenode.FSImage.loadEdits(FSImage.java:733)

at org.apache.hadoop.hdfs.server.namenode.ha.EditLogTailer.doTailEdits(EditLogTailer.java:227)

at org.apache.hadoop.hdfs.server.namenode.ha.EditLogTailer$EditLogTailerThread.doWork(EditLogTailer.java:321)

at org.apache.hadoop.hdfs.server.namenode.ha.EditLogTailer$EditLogTailerThread.access$200(EditLogTailer.java:279)

at org.apache.hadoop.hdfs.server.namenode.ha.EditLogTailer$EditLogTailerThread$1.run(EditLogTailer.java:296)

at org.apache.hadoop.security.SecurityUtil.doAsLoginUserOrFatal(SecurityUtil.java:456)

at org.apache.hadoop.hdfs.server.namenode.ha.EditLogTailer$EditLogTailerThread.run(EditLogTailer.java:292)

2013-09-26 10:44:41,917 INFO org.apache.hadoop.util.ExitUtil: Exiting with status 1