Enable archivelog mode in RAC

In 10g Release 1, the database must be mounted (not open) by an exclusive instance. In other words, set the CLUSTER_DATABASE parameter to FALSE. After executing the ALTER DATABASE SQL statement to change the archive log mode, shutdown the instance and restart it with the CLUSTER_DATABASE parameter set to TRUE before you restart the other instances.

1. Login to one of the nodes, disable the cluster instance parameter and set log archive destination:

$ sqlplus / as sysdba
SQL> alter system set cluster_database=false scope=spfile sid='';
SQL> alter system set log_archive_dest_1='' scope=spfile sid='*';

2. Shutdown all instances:

$ srvctl stop database -d 

3. Using the local instance, mount the database:

$ sqlplus / as sysdba
SQL> startup mount;

4. Enable archivelog mode

SQL> alter database archivelog;

5. Re-enable support for clustering from the current instance:

SQL> alter system set cluster_database=true scope=spfile sid='';

6. Shutdown the local instance:

SQL> shutdown immediate;

7. Bring all instances back up:

$ srvctl start database -d 

From 10g Release 2, you don't need to modify CLUSTER_DATABASE parameter to enable archivelog mode.

1. Login to one of the nodes, set log archive destination:

$ sqlplus / as sysdba
SQL> alter system set log_archive_dest_1='' scope=spfile sid='*';

2. Shutdown all instances:

$ srvctl stop database -d 

3. Using the local instance, mount the database:

$ sqlplus / as sysdba
SQL> startup mount;

4. Enable archivelog mode

SQL> alter database archivelog;

5. Shutdown the local instance:

SQL> shutdown immediate;

6. Bring all instances back up:

$ srvctl start database -d