今天启动数据库到MOUNT时，报
ORA-00205: error in identifying control file, check alert log for more info
打开ALERT.Log：
ALTER DATABASE MOUNT
Thu Jul 01 23:01:22 2010
Starting background process ASMB
ASMB started with pid=16, OS id=3644
Thu Jul 01 23:01:23 2010
ORA-00202: control file: '+DGGROUP/study/controlfile/current.257.722711849'
ORA-17503: ksfdopn:2 Failed to open file +DGGROUP/study/controlfile/current.257.722711849
ORA-15001: diskgroup "DGGROUP" does not exist or is not mounted
ORA-15055: unable to connect to ASM instance
ORA-01031: insufficient privileges
Thu Jul 01 23:01:22 2010
Starting background process ASMB
ASMB started with pid=16, OS id=3644
Thu Jul 01 23:01:23 2010
ORA-00202: control file: '+DGGROUP/study/controlfile/current.257.722711849'
ORA-17503: ksfdopn:2 Failed to open file +DGGROUP/study/controlfile/current.257.722711849
ORA-15001: diskgroup "DGGROUP" does not exist or is not mounted
ORA-15055: unable to connect to ASM instance
ORA-01031: insufficient privileges
Thu Jul 01 23:01:23 2010
ORA-205 signalled during: ALTER DATABASE MOUNT...
ORA-205 signalled during: ALTER DATABASE MOUNT...
试用ASMCMD，报ORA-01031。
解决方法：
在WINDOWS上，SQLNET.AUTHENTICATION_SERVICES 必须设定为NTS 才能连接上ASM。ASMCMD同样成功。
本文转自 anranran 51CTO博客，原文链接:http://blog.51cto.com/guojuanjun/342534