Implementing Oracle Standby (Data Guard) involves setting up a synchronized backup of the primary database for high availability and disaster recovery. Key steps include enabling **ARCHIVELOG** mode on the primary, creating and restoring a backup on the standby, configuring redo log shipping, and starting **Redo Apply** (for physical standby) or **SQL Apply** (for logical standby). Redo logs from the primary are continuously sent and applied on the standby, ensuring data synchronization. Regular testing of switchover (for maintenance) and failover (for failures) ensures that the standby can take over quickly if the primary fails, minimizing downtime and data loss.

✓ Install 12.1.0.2 binaries on both Primary and Standby Server.

✓ Shut down Primary Database.

✓ Shutdown Standby Database.

✓ At standby and standby database server copy init file and password file to new home

✓ Copy listener.ora and tnsnames.ora file to new Oracle home

✓ upgrade the primary database

✓ After successful completion of Primary database upgrade. Start recovery on a standby database using recover managed standby database disconnect; command

✓ Standby database will be upgraded through redo apply.

✓ After completion of all redo apply we can open a database in open mode.

To apply patch on physical standby database setup, 1st patch needs to be applied on standby, and then on primary. We will perform some steps like:

✓ Check the database_role for both database (select database_role from v$database;)

✓ Check log gap between primary and standby ( it should be zero)

✓ DISABLE SHIPPING ON PRIMARY

✓ CANCEL THE RECOVERY ON STANDBY

✓ Shutdown the listener and database in standby

✓ Check the patch conflict with ORACLE_HOME (prereq CheckConflictAgainstOHWithDetail)

✓ Now apply the patch(on standby)

✓ start the standby database in mount state and start the listener

✓ Now shutdown the database and listener in primary

✓go to patch location and unzip the patch

✓ Check the patch conflict with ORACLE_HOME

✓ Now apply the patch on primary

✓ Now start up open the database and listener.

✓ Enable archive shipping in primary

✓Start the recovery(MRP) on standby:

✓ Run the catbundle.sql script from PRIMARY

✓ Check the registry history in primary( this patch should be listed there)