Enable ARCHIVELOG and FLASHBACK mode on ASM

To enable ARCHIVELOG on ASM and configure FLASHBACK (without enabling it) you need to set up the appropriate initialization parameters (db_recovery_file_dest_size, db_recovery_file_dest, db_flashback_retention_target).

SQL>alter system set db_recovery_file_dest_size = '400G' scope=both sid='*';
SQL>alter system set db_recovery_file_dest = '+DATA_RAC3' scope=both sid='*';
SQL> alter system set db_flashback_retention_target = 60 scope=both sid='*';


Then you need to put the database in MOUNT mode; ARCHIVELOG and FLASHBACK mode can be changed only when the database is in the MOUNT state.
srvctl stop database -d RAC3 -o immediate
srvctl start database -d RAC3 -o mount


To enable ARCHIVELOG and FLASHBACK mode you should issue the following command
sql> ALTER DATABASE ARCHIVELOG;
sql> ALTER DATABASE FLASHBACK ON; (I didn't issue for my installation)

Then you can open your database and check its status.
sql> SELECT LOG_MODE,FLASHBACK_ON FROM V$DATABASE;
LOG_MODE FLASHBACK_ON
------------ ------------------
ARCHIVELOG NO (You should see YES)

Add a controlfile into ASM when original controlfile is stored on ASM

Some days ago I installed Oracle 11gR2 on a RAC formed by two nodes. The default installation on ASM use just a controlfile. So I decided to add another one and the following are the steps I've done.

I'm using of course an spfile for my instance.
From a sqlplus sessions I needed to know where my current controlfile was and then altered the system to add another one. So I typed:
sql> show parameter control_files
sql> alter system set control_files='+DATA_RAC3/rac3/controlfile/current.260.706989187', '+DATA_RAC3' scope=spfile sid='*';


After I needed to put the instance in NOMOUNT mode, so as the oracle user, I typed:
srvctl stop database -d RAC3 -o immediate


From rman I was able to duplicate the controlfile, using the following commands:
$ rman nocatalog
RMAN>connect target
RMAN> restore controlfile from '+DATA_RAC3/rac3/controlfile/current.260.706989187';

After those commands, I put the database in OPEN mode, always from RMAN console:
RMAN> sql 'alter database mount';
RMAN> sql 'alter database open;


From a new sqlplus session I was able to see my new duplicated controlfile:
sql> select name from v$controlfile;


And now the last step. I needed to alter again the system, modifing the control_file parameter with the complete path of the new file:
sql> alter system set control_files='+DATA_RAC3/rac3/controlfile/current.260.706989187', '+DATA_RAC3/rac3/controlfile/current.268.707763013' scope=spfile sid='*';