core-site.xml配置项：hadoop.tmp.dir

hadoop.tmp.dir：A base for other temporary directories.

集群运行后，修改该配置项后，发现类似错误：

2012-10-12 10:06:54,804 INFO org.apache.hadoop.hdfs.server.common.Storage: Storage directory /tmp/hadoop-grid/dfs/name does not exist.
2012-10-12 10:06:54,806 ERROR org.apache.hadoop.hdfs.server.namenode.FSNamesystem: FSNamesystem initialization failed.
org.apache.hadoop.hdfs.server.common.InconsistentFSStateException: Directory /tmp/hadoop-grid/dfs/name is in an inconsistent state: storage directory does not exist or is not accessible.
    at org.apache.hadoop.hdfs.server.namenode.FSImage.recoverTransitionRead(FSImage.java:290)
    at org.apache.hadoop.hdfs.server.namenode.FSDirectory.loadFSImage(FSDirectory.java:87)
    at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.initialize(FSNamesystem.java:311)
    at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.<init>(FSNamesystem.java:292)
    at org.apache.hadoop.hdfs.server.namenode.NameNode.initialize(NameNode.java:201)
    at org.apache.hadoop.hdfs.server.namenode.NameNode.<init>(NameNode.java:279)
    at org.apache.hadoop.hdfs.server.namenode.NameNode.createNameNode(NameNode.java:956)
    at org.apache.hadoop.hdfs.server.namenode.NameNode.main(NameNode.java:965)
2012-10-12 10:06:54,819 INFO org.apache.hadoop.ipc.Server: Stopping server on 9000

Hadoop无法找到dfs/name 这个dfs文件系统的域名空间文件。

重新配置了hadoop.tmp.dir 目录，必须重新格式hdfs。

hadoop namenode -format -cluster ns1