HADOOP报错Incompatible namespaceIDs

devil20

　　转自：http://blog.csdn.net/wh62592855/article/details/5752199
　　今早一来，突然发现使用-put命令往HDFS里传数据传不上去了，抱一大堆错误，然后我使用bin/hadoop dfsadmin -report查看系统状态
　　admin@adw1:/home/admin/joe.wangh/hadoop-0.19.2>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%: ?%
　　-------------------------------------------------
　　Datanodes available: 0 (0 total, 0 dead)
　　使用bin/stop-all.sh关闭HADOOP
　　admin@adw1:/home/admin/joe.wangh/hadoop-0.19.2>bin/stop-all.sh
　　stopping jobtracker
　　172.16.197.192: stopping tasktracker
　　172.16.197.193: stopping tasktracker
　　stopping namenode
　　172.16.197.193: no datanode to stop
　　172.16.197.192: no datanode to stop
　　172.16.197.191: stopping secondarynamenode
　　哦，看到了吧，发现datanode前面并没有启动起来。去DATANODE上查看一下日志
　　admin@adw2:/home/admin/joe.wangh/hadoop-0.19.2/logs>vi hadoop-admin-datanode-adw2.hst.ali.dw.alidc.net.log
　　************************************************************/
　　2010-07-21 10:12:11,987 ERROR org.apache.hadoop.hdfs.server.datanode.DataNode: java.io.IOException:  Incompatible namespaceIDs in  /home/admin/joe.wangh/hadoop/data/dfs.data.dir: namenode namespaceID =  898136669; datanode namespaceID = 2127444065
　　at org.apache.hadoop.hdfs.server.datanode.DataStorage.doTransition(DataStorage.java:233)
　　at org.apache.hadoop.hdfs.server.datanode.DataStorage.recoverTransitionRead(DataStorage.java:148)
　　at org.apache.hadoop.hdfs.server.datanode.DataNode.startDataNode(DataNode.java:288)
　　at org.apache.hadoop.hdfs.server.datanode.DataNode.(DataNode.java:206)
　　at org.apache.hadoop.hdfs.server.datanode.DataNode.makeInstance(DataNode.java:1239)
　　at org.apache.hadoop.hdfs.server.datanode.DataNode.instantiateDataNode(DataNode.java:1194)
　　at org.apache.hadoop.hdfs.server.datanode.DataNode.createDataNode(DataNode.java:1202)
　　at org.apache.hadoop.hdfs.server.datanode.DataNode.main(DataNode.java:1324)
　　......
　　错误提示namespaceIDs不一致。
　　下面给出两种解决办法，我使用的是第二种。

Workaround 1: Start from scratch  

I can testify that the following steps solve this error, but the side effects won't make you happy (me neither). The crude workaround I have found is to:

1.       stop the cluster

2.       delete the data directory on the problematic datanode: the directory is specified by dfs.data.dir in conf/hdfs-site.xml; if you followed this tutorial, the>

3.       reformat the namenode (NOTE: all HDFS data is lost during this process!)

4.       restart the cluster

When deleting all the HDFS data and starting from scratch does not sound like a good>

Workaround 2: Updating namespaceID of problematic datanodes  

Big thanks to Jared Stehler for the following suggestion. I have not tested it myself yet, but feel free to try it out and send me your feedback. This workaround is "minimally invasive" as you only have to edit one file on the problematic datanodes:

1.       stop the datanode

2.       edit the value of namespaceID in /current/VERSION to match the value of the current namenode

3.       restart the datanode

If you followed the instructions in my tutorials, the full path of the>

If you wonder how the contents of VERSION look like, here's one of mine:

#contents of /current/VERSION

namespaceID=393514426

storageID=DS-1706792599-10.10.10.1-50010-1204306713481

cTime=1215607609074

storageType=DATA_NODE

layoutVersion=-13

原因:每次namenode  format会重新创建一个namenodeId,而tmp/dfs/data下包含了上次format下的id,namenode  format清空了namenode下的数据,但是没有清空datanode下的数据,导致启动时失败,所要做的就是每次fotmat前,清空tmp一下 的所有目录.