hadoop 2.6 namenode创建失败

（前面都正常）
2016-03-23 08:30:10,036 WARN org.apache.hadoop.hdfs.server.namenode.FSNamesystem: Encountered exception loading fsimage
java.io.IOException: NameNode is not formatted.
at org.apache.hadoop.hdfs.server.namenode.FSImage.recoverTransitionRead(FSImage.java:212)
at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.loadFSImage(FSNamesystem.java:1020)
at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.loadFromDisk(FSNamesystem.java:739)
at org.apache.hadoop.hdfs.server.namenode.NameNode.loadNamesystem(NameNode.java:536)
at org.apache.hadoop.hdfs.server.namenode.NameNode.initialize(NameNode.java:595)
at org.apache.hadoop.hdfs.server.namenode.NameNode.(NameNode.java:762)
at org.apache.hadoop.hdfs.server.namenode.NameNode.(NameNode.java:746)
at org.apache.hadoop.hdfs.server.namenode.NameNode.createNameNode(NameNode.java:1438)
at org.apache.hadoop.hdfs.server.namenode.NameNode.main(NameNode.java:1504)
2016-03-23 08:30:10,040 INFO org.mortbay.log: Stopped HttpServer2$SelectChannelConnectorWithSafeStartup@0.0.0.0:50070
2016-03-23 08:30:10,140 INFO org.apache.hadoop.metrics2.impl.MetricsSystemImpl: Stopping NameNode metrics system...
2016-03-23 08:30:10,141 INFO org.apache.hadoop.metrics2.impl.MetricsSystemImpl: NameNode metrics system stopped.
2016-03-23 08:30:10,141 INFO org.apache.hadoop.metrics2.impl.MetricsSystemImpl: NameNode metrics system shutdown complete.
2016-03-23 08:30:10,141 FATAL org.apache.hadoop.hdfs.server.namenode.NameNode: Failed to start namenode.
java.io.IOException: NameNode is not formatted.
at org.apache.hadoop.hdfs.server.namenode.FSImage.recoverTransitionRead(FSImage.java:212)
at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.loadFSImage(FSNamesystem.java:1020)
at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.loadFromDisk(FSNamesystem.java:739)
at org.apache.hadoop.hdfs.server.namenode.NameNode.loadNamesystem(NameNode.java:536)
at org.apache.hadoop.hdfs.server.namenode.NameNode.initialize(NameNode.java:595)
at org.apache.hadoop.hdfs.server.namenode.NameNode.(NameNode.java:762)
at org.apache.hadoop.hdfs.server.namenode.NameNode.(NameNode.java:746)
at org.apache.hadoop.hdfs.server.namenode.NameNode.createNameNode(NameNode.java:1438)
at org.apache.hadoop.hdfs.server.namenode.NameNode.main(NameNode.java:1504)
2016-03-23 08:30:10,142 INFO org.apache.hadoop.util.ExitUtil: Exiting with status 1
2016-03-23 08:30:10,144 INFO org.apache.hadoop.hdfs.server.namenode.NameNode: SHUTDOWN_MSG:
/************************************************************
SHUTDOWN_MSG: Shutting down NameNode at localhost.localdomain/127.0.0.1
************************************************************/