java.io.IOException: File /user/root/input could only be replicated to 0 nodes, instead of 1
at org.apache.Hadoop.hdfs.server.namenode.FSNamesystem.getAdditionalBlock(FSNamesystem.java:1271)
at org.apache.hadoop.hdfs.server.namenode.NameNode.addBlock(NameNode.java:422)
at sun.reflect.GeneratedMethodAccessor7.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.apache.hadoop.ipc.RPC$Server.call(RPC.java:508)
at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:959)
at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:955)
at java.security.AccessController.doPrivileged(Native Method)
at javax.security.auth.Subject.doAs(Subject.java:396)
at org.apache.hadoop.ipc.Server$Handler.run(Server.java:953)
org.apache.hadoop.ipc.RemoteException: java.io.IOException: File /user/root/input could only be replicated to 0 nodes, instead of 1
at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.getAdditionalBlock(FSNamesystem.java:1271)
at org.apache.hadoop.hdfs.server.namenode.NameNode.addBlock(NameNode.java:422)
at sun.reflect.GeneratedMethodAccessor7.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.apache.hadoop.ipc.RPC$Server.call(RPC.java:508)
at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:959)
at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:955)
at java.security.AccessController.doPrivileged(Native Method)
at javax.security.auth.Subject.doAs(Subject.java:396)
at org.apache.hadoop.ipc.Server$Handler.run(Server.java:953)
at org.apache.hadoop.ipc.Client.call(Client.java:740)
at org.apache.hadoop.ipc.RPC$Invoker.invoke(RPC.java:220)
at $Proxy0.addBlock(Unknown Source)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.apache.hadoop.io.retry.RetryInvocationHandler.invokeMethod(RetryInvocationHandler.java:82)
at org.apache.hadoop.io.retry.RetryInvocationHandler.invoke(RetryInvocationHandler.java:59)
at $Proxy0.addBlock(Unknown Source)
at org.apache.hadoop.hdfs.DFSClient$DFSOutputStream.locateFollowingBlock(DFSClient.java:2937)
at org.apache.hadoop.hdfs.DFSClient$DFSOutputStream.nextBlockOutputStream(DFSClient.java:2819)
at org.apache.hadoop.hdfs.DFSClient$DFSOutputStream.access$2000(DFSClient.java:2102)
at org.apache.hadoop.hdfs.DFSClient$DFSOutputStream$DataStreamer.run(DFSClient.java:2288)
原因：Configured Capacity也就是datanode 没用分配容量
[root@dev9106 bin]# ./hadoop dfsadmin -report
Configured Capacity: 0 (0 KB)
Present Capacity: 0 (0 KB)
DFS Remaining: 0 (0 KB)
DFS Used: 0 (0 KB)
DFS Used%: ?%
Under replicated blocks: 0
Blocks with corrupt replicas: 0
Missing blocks: 0
解决方法：
1. 查看你的文件系统
[root@dev9106 /]# df -hl
文件系统 容量 已用 可用 已用% 挂载点
/dev/sda3 1.9G 1.6G 302M 84% /
/dev/sda8 845G 47G 756G 6% /home
/dev/sda7 5.7G 147M 5.3G 3% /tmp
/dev/sda6 9.5G 4.0G 5.1G 45% /usr
/dev/sda5 9.5G 273M 8.8G 3% /var
/dev/sda1 190M 15M 167M 8% /boot
tmpfs 7.8G 0 7.8G 0% /dev/shm
2. 修改文件Hadoop conf/core-site.xml 中hadoop.tmp.dir的值
<property>
<name>fs.default.name</name>
<value>hdfs://localhost:9000</value>
</property>
<property>
<name>hadoop.tmp.dir</name>
<value>/home/dhfs/tmp</value>
</property>
</configuration>
3. 停止hadoop服务，重新格式化namenode
4.重启服务
5.Ok
2. 运行hadoop程序时， 中途我把它终止了，然后再向hdfs加文件或删除文件时，出现Name node is in safe mode错误：
rmr: org.apache.hadoop.dfs.SafeModeException: Cannot delete /user/hadoop/input. Name node is in safe mode
解决的命令：
bin/hadoop dfsadmin -safemode leave 关闭safe mode
