hadoop格式化失败原因:format is aborted

user6@das0 hadoop-0.20.203.0]$ bin/hadoop namenode -format

12/02/20 14:05:17 INFO namenode.NameNode: STARTUP_MSG: 

Re-format filesystem in /data0/hadoop-name ? (Y or N) y

Format aborted in /data0/hadoop-name

12/02/20 14:05:20 INFO namenode.NameNode: SHUTDOWN_MSG: 

随后启动hadoop, 发现http://das0:5007无法显示。

将/data0/hadoop-name文件夹整个删除。然后再格，成功！！！

[zhangpeng6@das0 hadoop-0.20.203.0]$ bin/hadoop namenode -format

12/02/20 14:09:57 INFO namenode.NameNode: STARTUP_MSG: 

12/02/20 14:09:57 INFO util.GSet: VM type       = 64-bit

12/02/20 14:09:57 INFO util.GSet: 2% max memory = 177.77875 MB

12/02/20 14:09:57 INFO util.GSet: capacity      = 2^24 = 16777216 entries

12/02/20 14:09:57 INFO util.GSet: recommended=16777216, actual=16777216

12/02/20 14:09:57 INFO namenode.FSNamesystem: fsOwner=zhangpeng6

12/02/20 14:09:57 INFO namenode.FSNamesystem: supergroup=supergroup

12/02/20 14:09:57 INFO namenode.FSNamesystem: isPermissionEnabled=true

12/02/20 14:09:57 INFO namenode.FSNamesystem: dfs.block.invalidate.limit=100

12/02/20 14:09:57 INFO namenode.FSNamesystem: isAccessTokenEnabled=false accessKeyUpdateInterval=0 min(s), accessTokenLifetime=0 min(s)

12/02/20 14:09:57 INFO namenode.NameNode: Caching file names occuring more than 10 times 

12/02/20 14:09:57 INFO common.Storage: Image file of size 116 saved in 0 seconds.

12/02/20 14:09:57 INFO common.Storage: Storage directory /data0/hadoop-name/namenode has been successfully formatted.

12/02/20 14:09:57 INFO namenode.NameNode: SHUTDOWN_MSG: 

问题总结：

在对namenode格式化之前，要确保dfs.name.dir参数指定的目录不存在。

Hadoop这样做的目的是防止错误地将已存在的集群格式化了

转自：http://blog.sina.com.cn/s/blog_48a45b9501011z7d.html