When the database was created, both the instances were running good.
Recently one instance was down due to some reason and we are not able to start the instance successfully.
When we are trying to start the instance , it says , it cant identify the control file. But the other instance is able to start and stop successfully.
When we start the database , we get the following error ...
ORA-00205: error in identifying control file, check alert log for more info
Then we changed the group ownership of Oracle executable to OS ASM group using below command after logging as ROOT user :
"This allows the database instance to access the ASM disks without having to make the database software owner a member of the OS ASM group."
Then re-login newly as ORACLE user and then started ORACLE Database instance.
Hope it helps