hadoop hdfs空间满后重新启动不了

server检查的时候，发现存在HDFS上的文件无法同步。再发现hadoop停掉了。

进行重新启动，重新启动不成功。

查看hadoop日志：

2014-07-30 14:15:42,025 INFO org.apache.hadoop.hdfs.server.namenode.FSNamesystem: Roll Edit Log from 192.168.206.133
<span style="color:#ff0000;">2014-07-30 14:15:42,026 WARN org.apache.hadoop.hdfs.server.namenode.FSNamesystem: Cannot roll edit log, edits.new files already exists in all healthy directories:
  /home/hadoop/hdfs/name/current/edits.new</span>

<span style="color:#ff0000;">2014-07-30 14:17:17,853 ERROR org.apache.hadoop.hdfs.server.namenode.FSNamesystem: Unable to sync edit log.
java.io.IOException: No space left on device</span>
	at sun.nio.ch.FileChannelImpl.force0(Native Method)
	at sun.nio.ch.FileChannelImpl.force(FileChannelImpl.java:348)
	at org.apache.hadoop.hdfs.server.namenode.FSEditLog$EditLogFileOutputStream.flushAndSync(FSEditLog.java:215)
	at org.apache.hadoop.hdfs.server.namenode.EditLogOutputStream.flush(EditLogOutputStream.java:89)
	at org.apache.hadoop.hdfs.server.namenode.FSEditLog.logSync(FSEditLog.java:1017)
	at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.startFile(FSNamesystem.java:1190)
	at org.apache.hadoop.hdfs.server.namenode.NameNode.create(NameNode.java:628)
	at sun.reflect.GeneratedMethodAccessor300.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
	at java.lang.reflect.Method.invoke(Method.java:597)
	at org.apache.hadoop.ipc.RPC$Server.call(RPC.java:563)
	at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:1388)
	at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:1384)
	at java.security.AccessController.doPrivileged(Native Method)
	at javax.security.auth.Subject.doAs(Subject.java:396)
	at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1121)
	at org.apache.hadoop.ipc.Server$Handler.run(Server.java:1382)
2014-07-30 14:17:17,853 FATAL org.apache.hadoop.hdfs.server.namenode.FSNamesystem: No edit streams are accessible
java.lang.Exception: No edit streams are accessible
	at org.apache.hadoop.hdfs.server.namenode.FSEditLog.fatalExit(FSEditLog.java:388)
	at org.apache.hadoop.hdfs.server.namenode.FSEditLog.exitIfNoStreams(FSEditLog.java:407)
	at org.apache.hadoop.hdfs.server.namenode.FSEditLog.removeEditsAndStorageDir(FSEditLog.java:432)
	at org.apache.hadoop.hdfs.server.namenode.FSEditLog.removeEditsStreamsAndStorageDirs(FSEditLog.java:470)
	at org.apache.hadoop.hdfs.server.namenode.FSEditLog.logSync(FSEditLog.java:1030)
	at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.startFile(FSNamesystem.java:1190)
	at org.apache.hadoop.hdfs.server.namenode.NameNode.create(NameNode.java:628)
	at sun.reflect.GeneratedMethodAccessor300.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$Server.call(RPC.java:563)
	at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:1388)
	at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:1384)
	at java.security.AccessController.doPrivileged(Native Method)
	at javax.security.auth.Subject.doAs(Subject.java:396)
	at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1121)
	at org.apache.hadoop.ipc.Server$Handler.run(Server.java:1382)

空间满了。

使用命令df -h查看当中一个datanode。果然

但使用du -s查看，但显示仅仅使用几百G，并没有满

这个实候确实让人费解，仅仅好重新启动datanode所在的server，并又一次挂载。回复原样，容量显示正常。

可是这个时候hadoop集群依旧无法重新启动，一直报错：

014-07-30 16:27:46,610 ERROR org.apache.hadoop.hdfs.server.namenode.FSNamesystem: FSNamesystem initialization failed.
java.io.IOException: Incorrect data format. logVersion is -32 but writables.length is 0.
	at org.apache.hadoop.hdfs.server.namenode.FSEditLog.loadFSEdits(FSEditLog.java:560)
	at org.apache.hadoop.hdfs.server.namenode.FSImage.loadFSEdits(FSImage.java:1026)
	at org.apache.hadoop.hdfs.server.namenode.FSImage.loadFSImage(FSImage.java:839)
	at org.apache.hadoop.hdfs.server.namenode.FSImage.recoverTransitionRead(FSImage.java:377)
	at org.apache.hadoop.hdfs.server.namenode.FSDirectory.loadFSImage(FSDirectory.java:100)
	at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.initialize(FSNamesystem.java:388)
	at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.<init>(FSNamesystem.java:362)
	at org.apache.hadoop.hdfs.server.namenode.NameNode.initialize(NameNode.java:276)
	at org.apache.hadoop.hdfs.server.namenode.NameNode.<init>(NameNode.java:496)
	at org.apache.hadoop.hdfs.server.namenode.NameNode.createNameNode(NameNode.java:1279)
	at org.apache.hadoop.hdfs.server.namenode.NameNode.main(NameNode.java:1288)
2014-07-30 16:27:46,612 ERROR org.apache.hadoop.hdfs.server.namenode.NameNode: java.io.IOException: Incorrect data format. logVersion is -32 but writables.length is 0.
	at org.apache.hadoop.hdfs.server.namenode.FSEditLog.loadFSEdits(FSEditLog.java:560)
	at org.apache.hadoop.hdfs.server.namenode.FSImage.loadFSEdits(FSImage.java:1026)
	at org.apache.hadoop.hdfs.server.namenode.FSImage.loadFSImage(FSImage.java:839)
	at org.apache.hadoop.hdfs.server.namenode.FSImage.recoverTransitionRead(FSImage.java:377)
	at org.apache.hadoop.hdfs.server.namenode.FSDirectory.loadFSImage(FSDirectory.java:100)
	at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.initialize(FSNamesystem.java:388)
	at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.<init>(FSNamesystem.java:362)
	at org.apache.hadoop.hdfs.server.namenode.NameNode.initialize(NameNode.java:276)
	at org.apache.hadoop.hdfs.server.namenode.NameNode.<init>(NameNode.java:496)
	at org.apache.hadoop.hdfs.server.namenode.NameNode.createNameNode(NameNode.java:1279)
	at org.apache.hadoop.hdfs.server.namenode.NameNode.main(NameNode.java:1288)

不得解，仅仅好从secondrynamenode尝试恢复

1. 先备份namenode和secondrynamenode的数据

2. 运行checkpoint数据：hadoop namenode –importCheckpoint

失败……

最后查了网上的方法(有一个是改动代码并又一次编译的。就算了)：

printf "\xff\xff\xff\xee\xff" > edits

重新启动失败。继续：

printf "\xff\xff\xff\xee\xff" > edits.new

重新启动成功。

可是问题来了。数据丢失，由于清空了edits文件最新的日志内容。

一般来说。到这份上是没有办法了。

可是，幸好我们有两地同步和备份。将别一个数据中心HDFS集群的数据同步过来，恢复成功。

假设没有异地备份的话。上面的操作我也会慎之又慎的。