hadoop多次格式化后，导致datanode启动不了

hadoop namenode -format
多次格式化后，datanode启动不了

org.apache.hadoop.ipc.RemoteException(java.io.IOException): File /user/beifeng/core-site.xml._COPYING_ could only be replicated to 0 nodes instead of minReplication (=1).  There are 0 datanode(s) running and no node(s) are excluded in this operation.
        at org.apache.hadoop.hdfs.server.blockmanagement.BlockManager.chooseTarget(BlockManager.java:1471)
        at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.getAdditionalBlock(FSNamesystem.java:2791)
        at org.apache.hadoop.hdfs.server.namenode.NameNodeRpcServer.addBlock(NameNodeRpcServer.java:606)
        at org.apache.hadoop.hdfs.protocolPB.ClientNamenodeProtocolServerSideTranslatorPB.addBlock(ClientNamenodeProtocolServerSideTranslatorPB.java:455)
        at org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos$ClientNamenodeProtocol$2.callBlockingMethod(ClientNamenodeProtocolProtos.java)
        at org.apache.hadoop.ipc.ProtobufRpcEngine$Server$ProtoBufRpcInvoker.call(ProtobufRpcEngine.java:585)
        at org.apache.hadoop.ipc.RPC$Server.call(RPC.java:928)
        at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:2013)
        at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:2009)
        at java.security.AccessController.doPrivileged(Native Method)
        at javax.security.auth.Subject.doAs(Subject.java:415)
        at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1614)
        at org.apache.hadoop.ipc.Server$Handler.run(Server.java:2007)

        at org.apache.hadoop.ipc.Client.call(Client.java:1411)
        at org.apache.hadoop.ipc.Client.call(Client.java:1364)
        at org.apache.hadoop.ipc.ProtobufRpcEngine$Invoker.invoke(ProtobufRpcEngine.java:206)
        at com.sun.proxy.$Proxy14.addBlock(Unknown Source)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:606)
        at org.apache.hadoop.io.retry.RetryInvocationHandler.invokeMethod(RetryInvocationHandler.java:187)
        at org.apache.hadoop.io.retry.RetryInvocationHandler.invoke(RetryInvocationHandler.java:102)
        at com.sun.proxy.$Proxy14.addBlock(Unknown Source)
        at org.apache.hadoop.hdfs.protocolPB.ClientNamenodeProtocolTranslatorPB.addBlock(ClientNamenodeProtocolTranslatorPB.java:368)
        at org.apache.hadoop.hdfs.DFSOutputStream$DataStreamer.locateFollowingBlock(DFSOutputStream.java:1449)
        at org.apache.hadoop.hdfs.DFSOutputStream$DataStreamer.nextBlockOutputStream(DFSOutputStream.java:1270)
        at org.apache.hadoop.hdfs.DFSOutputStream$DataStreamer.run(DFSOutputStream.java:526)
put: File /user/beifeng/core-site.xml._COPYING_ could only be replicated to 0 nodes instead of minReplication (=1).  There are 0 datanode(s) running and no node(s) are excluded in this operation.

0.20.2版本解决方式:
1、查看名称节点上(即在配置文件中配置的hadoop.tmp.dir参数路径)/usr/hadoop0.20.2/hadoop-huanghz/dfs/name/current/文件夹中VERSION文件中的namespaceid；
2、在两个数据节点修改上dfs.data.dir配置的路径下current文件夹中的VERSION文件namespaceid与名称节点保持一致

2.20版本解决
/data/hadoop/dfs/name/current/VERSION
用name下面的clusterID，修改datanode的/data/hadoop/dfs/data/current/VERSION 里面的clusterID
每次格式化，name下面的VERSION的clusterID会产生一个新的ID，要去修改各个节点的VERSION的clusterID 

……/dfs/data/current


storageID=DS-1959445666-10.161.138.100-50010-1386493413986
clusterID=CID-64a3a726-29e4-4d80-86a6-035ef33a225b
cTime=0
storageType=DATA_NODE
layoutVersion=-47

……/dfs/name/current/VERSION
#Fri Jan 03 10:37:48 CST 2014
namespaceID=1667984727
clusterID=CID-42c6d540-c3ca-44df-95e8-01a6d87effb5
cTime=0
storageType=NAME_NODE
blockpoolID=BP-220196921-10.161.138.100-1388716668863
layoutVersion=-47