HOWTO: Enable Archivelog Mode in a RAC database

1. Change the cluster database parameter so the database can be mounted in exclusive mode which is required to enable archive logging

alter system set cluster_database=false scope=spfile;

2. Shutdown the database using srvctl

srvctl stop database -d ORA

3. Startup one of the instances upto the mount state

sqlplus / as sysdba

startup mount

4. Enable archivelog mode

alter database archivelog;

5. Change the cluster_database parameter back to true in the spfile

alter system set cluster_database=true scope=spfile;

6. Shutdown the instance

shutdown immediate

7. Startup the database using srvctl

srvctl start database -d ORA

8. Once the database is back up you can verify the change by connecting to one of the database instances

sqlplus / as sysdba

archive log list

For example:

SQL> archive log list
Database log mode Archive Mode
Automatic archival Enabled
Archive destination /archlogs/ORA/
Oldest online log sequence 1
Next log sequence to archive 3
Current log sequence 3

Simple as that.

Notes:

You don’t need to set log_archive_dest1 as it defaults to the flash recovery area (ie USE_DB_RECOVERY_FILE_DEST) although you’ll need to make sure it is large enough for your needs.