Enable archive log mode in RAC database

Case:

To enable archive log mode in an 11gR2 RAC database.


Steps:

Need to shutdown all instances of the RAC and then "MOUNT"  a single node to switch it to ARCHIVELOG mode. It is recommended to have more than one archive destination.

It is better to keep ArchiveLogs on shared storage because any node of the cluster can be used to backup the ArchiveLogs. If we are using FRA as backup location then it makes sense to keep the files there.


ALTER SYSTEM SET log_archive_dest_1='location=/app/db_backup/archive/ORCL/' SCOPE=spfile; 
ALTER SYSTEM SET log_archive_format='arch_%t_%s_%r.arc' SCOPE=spfile;

Set cluster_database parameter to false since we have to mount the database in exclusive mode. 
.
ALTER SYSTEM SET cluster_database=FALSE SCOPE=spfile;

srvctl stop database -d ORCL

STARTUP MOUNT;

Since the datafiles and spfile are shared between all instances this operation only has to be done from a single node.

ALTER DATABASE ARCHIVELOG;
ALTER SYSTEM SET cluster_database=TRUE SCOPE=spfile;
SHUTDOWN IMMEDIATE;

srvctl start database -d ORCL


Disabling:

Follow similar steps to disable archiving.

ALTER SYSTEM SET cluster_database=FALSE SCOPE=spfile;

srvctl stop database -d ORCL

STARTUP MOUNT;

alter database noarchivelog;

ALTER SYSTEM SET cluster_database=TRUE SCOPE=spfile;

SHUTDOWN IMMEDIATE;

srvctl start database -d ORCL