Below is the step-by-step procedure to enable ARCHIVELOG mode in an Oracle 12c RAC database. This process ensures that your database can perform point-in-time recoveries and maintain a high level of data protection.
Initial Status Check and Database Shutdown
Before making architectural changes, verify the current state of your RAC instances across all nodes.
[oracle@testsrv1 ~]$ srvctl status database -d MYTESTDB Instance MYTESTDB1 is running on node testsrv1 Instance MYTESTDB2 is running on node testsrv2
Stopping the Database Instances
To change the archiving mode, the database must be in a mounted state but not open. Begin by shutting down all instances in the cluster.
[oracle@testsrv1 ~]$ srvctl stop database -d MYTESTDB [oracle@testsrv1 ~]$ srvctl status database -d MYTESTDB Instance MYTESTDB1 is not running on node testsrv1 Instance MYTESTDB2 is not running on node testsrv2
Starting the Database in Mount Mode
In a RAC environment, you can use srvctl to bring all instances into the MOUNT state simultaneously.
[oracle@testsrv1 ~]$ srvctl start database -d MYTESTDB -o mount [oracle@testsrv1 ~]$ srvctl status database -d MYTESTDB Instance MYTESTDB1 is running on node testsrv1 Instance MYTESTDB2 is running on node testsrv2
Verifying Instance Status via SQL*Plus
Connect to the local instance to verify that all cluster members are correctly mounted.
[oracle@testsrv1 ~]$ sqlplus '/ as sysdba' SQL*Plus: Release 12.1.0.2.0 Production on Fri Oct 14 00:10:28 2016 Copyright (c) 1982, 2014, Oracle. All rights reserved. SQL> select instance_name,status from gv$instance; INSTANCE_NAME STATUS ---------------- ------------ MYTESTDB1 MOUNTED MYTESTDB2 MOUNTED
Enabling ARCHIVELOG Mode
Now that the instances are mounted, you can check the current log mode and execute the conversion.
SQL> archive log list; Database log mode No Archive Mode Automatic archival Disabled Archive destination /u01/app/oracle/product/12.1.0.2/dbhome_1/dbs/arch Oldest online log sequence 32 Current log sequence 33 SQL> alter database archivelog; Database altered.
Configuring the Archive Destination (FRA)
It is best practice to point your archive logs to a shared area, such as the Fast Recovery Area (FRA) on ASM, so all RAC nodes can access them.
SQL> alter system set log_archive_dest_1='LOCATION=+FRA' SCOPE=SPFILE; SQL> exit
Final Restart and Verification
To complete the process, shut down the mounted instances and perform a clean start to open the database
[oracle@testsrv1 ~]$ srvctl stop database -d MYTESTDB [oracle@testsrv1 ~]$ srvctl start database -d MYTESTDB
Confirming the New Configuration
Finally, log back in to ensure that automatic archival is enabled and pointing to the correct destination.
[oracle@testsrv1 ~]$ sqlplus '/ as sysdba' SQL> archive log list; Database log mode Archive Mode Automatic archival Enabled Archive destination +FRA Oldest online log sequence 33 Next log sequence to archive 34 Current log sequence 34
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