Enabling ArchiveLog Mode in a RAC Environment

Login to one of the nodes (i.e. linux1) and disable the cluster instance parameter by setting cluster_database to FALSE from the current instance:
$ sqlplus “/ as sysdba”
SQL> alter system set cluster_database=false scope=spfile sid=’orcl1′;

Shutdown all instances accessing the clustered database:
$ srvctl stop database -d orcl

Using the local instance, MOUNT the database:
$ sqlplus “/ as sysdba”
SQL> startup mount
Enable archiving:
SQL> alter database archivelog;

Re-enable support for clustering by modifying the instance parameter cluster_database to TRUE from the current instance:
SQL> alter system set cluster_database=true scope=spfile sid=’orcl1′;
Shutdown the local instance:
SQL> shutdown immediate

Bring all instance back up using srvctl:
$ srvctl start database -d orcl
(Optional) Bring any services (i.e. TAF) back up using srvctl:
$ srvctl start service -d orcl

Login to the local instance and verify Archive Log Mode is enabled:
$ sqlplus “/ as sysdba”
SQL> archive log list
Database log mode Archive Mode
Automatic archival Enabled
Archive destination USE_DB_RECOVERY_FILE_DEST
Oldest online log sequence 83
Next log sequence to archive 84
Current log sequence 84