错误

[root@hadoop test]# hadoop jar hadoop.jarcom.hadoop.hdfs.CopyToHDFS
14/01/26 10:20:00 WARN hdfs.DFSClient: DataStreamerException: org.apache.hadoop.ipc.RemoteException: java.io.IOException: File/user/hadoop/test/01/hello.txt could only be replicated to 0 nodes, instead of1
         atorg.apache.hadoop.hdfs.server.namenode.FSNamesystem.getAdditionalBlock(FSNamesystem.java:1639)
         atorg.apache.hadoop.hdfs.server.namenode.NameNode.addBlock(NameNode.java:736)
         atsun.reflect.GeneratedMethodAccessor6.invoke(Unknown Source)
 
14/01/26 10:20:00 WARN hdfs.DFSClient: Error Recoveryfor block null bad datanode[0] nodes == null
14/01/26 10:20:00 WARN hdfs.DFSClient: Could not getblock locations. Source file "/user/hadoop/test/01/hello.txt" -Aborting...
Exception in thread "main"org.apache.hadoop.ipc.RemoteException: java.io.IOException: File/user/hadoop/test/01/hello.txt could only be replicated to 0 nodes, instead of1
         atorg.apache.hadoop.hdfs.server.namenode.FSNamesystem.getAdditionalBlock(FSNamesystem.java:1639)
         atorg.apache.hadoop.hdfs.server.namenode.NameNode.addBlock(NameNode.java:736)
         atsun.reflect.GeneratedMethodAccessor6.invoke(Unknown Source)
         atsun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
        
14/01/26 10:20:00 ERROR hdfs.DFSClient: Failed to closefile /user/hadoop/test/01/hello.txt
org.apache.hadoop.ipc.RemoteException:java.io.IOException: File /user/hadoop/test/01/hello.txt could only bereplicated to 0 nodes, instead of 1
         atorg.apache.hadoop.hdfs.server.namenode.FSNamesystem.getAdditionalBlock(FSNamesystem.java:1639)
         atorg.apache.hadoop.hdfs.server.namenode.NameNode.addBlock(NameNode.java:736)
         atsun.reflect.GeneratedMethodAccessor6.invoke(Unknown Source)
         atsun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
         ient.java:2989)

2.究其原因并制定解决方案：

原因：

多次格式化hadoop导致版本信息不一致，修改为一致状态即可解决问题

解决

1、先把服务都停掉     stop-all.sh

2、格式化namenode   hadoop namenode -foramt

3、重新启动所有服务   start-all.sh

4、可以进行正常操作了 

注：

   这里格式化很可能出现格式失败的情况，这里就不在细说失败的原有和解决方法，不清楚的同学可以参考博文：http://blog.csdn.net/yangkai_hudong/article/details/18731395

3.网上其它相关的解决资料

1,现象：flume再往Hadoop HDFS写文件时flume.log报错 be replicated to 0 nodes, instead of 1

2012-12-18 13:47:24,673 WARN hdfs.BucketWriter: CaughtIOException writing to HDFSWriter (java.io.IOException: File/logdata/20121218/bj4aweb04/8001_4A_ACA/8001_4A_ACA.1355799411582.tmp couldonly be replicated to 0 nodes, instead of 1
        at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.getAdditionalBlock(FSNamesystem.java:1558)
        atorg.apache.hadoop.hdfs.server.namenode.NameNode.addBlock(NameNode.java:696)

2，查看相关进程状态 datanode没有正常启动

 [hadoop@dtydb6 hadoop]$ jps
7427 Jps
7253 TaskTracker
6576 NameNode
6925 SecondaryNameNode
7079 JobTracker
 
 3，查看datanode的日志

Incompatible namespaceIDs
 java.io.IOException: Incompatible namespaceIDs in /hadoop/logdata:namenode namespaceID = 13513664; datanode namespaceID = 525507667

4，根据报错信息定位到namespaceIDs版本不一致

根据参考文档的解决方案，原因是多次格式化hadoop导致版本信息不一致，修改为一致状态即可解决问题
解决的办法很简单，两个方案

1）. 所有的datanode删掉，重新建（很麻烦，但看你了）
2）登上datanode，把位于{dfs.data.dir}/current/VERSION中的namespaceID改为最新的版本即可

[hadoop@dtydb6 current]$ cat VERSION
#Fri Dec 14 09:37:22 CST 2012
namespaceID=525507667
storageID=DS-120876865-10.4.124.236-50010-1354772633249
cTime=0
storageType=DATA_NODE
layoutVersion=-32

5，重新启动hadoop，datanode已经成功启动
[hadoop@dtydb6 current]$ jps
8770 JobTracker
8436 DataNode
8266 NameNode
8614 SecondaryNameNode

hadoop报错：could only be replicated to 0 nodes, instead of 1