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I see what you mean. I had to use an Oracle 10 document for the second command as noted below :
BACKUP CURRENT CONTROLFILE - Making a Manual Backup of the Control File of the database you are backing up.
Source : Database Backup and Recovery User's Guide 11g Release 2 (11.2) E10642-03
Section 9 Backing Up Control Files with RMAN
BACKUP CURRENT CONTROLFILE FOR STANDBY - Create the standby control file with this command.
Source : Data Guard Concepts and Administration 10g Release 2 (10.2) B14239-05
Section F.1.2 Creating the Standby Control File with RMAN
Oddly not found in Section F "Creating a Standby Database with Recovery Manager"
Of : Data Guard Concepts and Administration 11g Release 2 (11.2) E10700-02
BACKUP CURRENT CONTROLFILE --> will backup the current control file which can be used to resore a database and later recover.
BACKUP CURRENT CONTROLFILE FOR STANDBY--> This statement is more used in a dataguard env.
In releases prior to release 8.1.7, you were required to create the standby control file with the SQL ALTER DATABASE statement. Now, you can use RMAN to make a special backup of the primary database control file that is usable as a standby database control file. A normal backup of controlfile cannoy be used while creating a standby database.
Thank you very much, Mseberg. After your advice, I even found the description of FOR STANDBY clause in Oracle® Database Backup and Recovery Reference 10g Release 2 (10.2). The Backup and Recovery Reference (BRR) of 11g was the primary source where I've tried to find the description. It's very oddly indeed that BRR 11g ignore this clause. I've posted the question to Oracle via the comments form on the BRR 11g documentation page.
Lets take it from scratch,
What is a controlfile:--> Its a small binary file which records the physcal structure of the database.
The control file includes:
The database name
Names and locations of associated datafiles and redo log files
The timestamp of the database creation
The current log sequence number
Now coming down to backup controlfile--> will have the exact backup of the controlfile being used by the database ( including the role of the database) please note that this controlfile cannot be used as a standby controlfile as when you try to use this it will throw error
Backup controlfile as standby--> will have every thing similar as to the previous command except for the database role flag which will not be primary but would be pahysical standby, all the other information would be same ...as with out it there wont be an exact replica of the primary database.
This is the only diffrence from what i understand of the concepts.
A normal controlfile (copy of primary controlfile) cannot be used to create the standby database. Instead, you need to have a standby copy of the primary controlfile to create the standby.
Say, if you have used a normal controlfile and not the standby controlfile, then you would face errors as shown below
SQL> alter database mount standby database;Also, you can refer this http://esemrick.blogspot.in/2006/02/backup-control-files-are-they-special.html
alter database mount standby database
ERROR at line 1:
ORA-01665: controlfile is not a standby controlfile
Might serve helpful.
You can find this on the Oracle® Data Guard Concepts and Administration 11g Release 2 (11.2) in section +3.2.2 Create a Control File for the Standby Database+ http://docs.oracle.com/cd/E11882_01/server.112/e25608/create_ps.htm#i68937
It does not go into details, but just explain what you have found on the older versions.