Oracle 19c Dataguard Installation with DG Broker

Oracle 19c Physical Standby Creation & Management (RMAN Duplicate + Data Guard Broker)

This article walks through building a physical standby using RMAN DUPLICATE FROM ACTIVE DATABASE, then managing switchover / failover with the Data Guard Broker. The commands were tested on Oracle Linux 8 with Oracle Database 19c.

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Assumptions

• Two hosts (oracle1.localdomain & oracle2.localdomain) with Oracle 19c installed.
• Primary instance runs on oracle1; standby will be created on oracle2.
• Listener port 1521 is reachable in both directions (check firewalls).
• Primary DB name MYDBPROD; standby unique name MYDBDG.

1 – Primary Server Preparation

1.1 Switch to ARCHIVELOG & Force Logging

-- Check mode
SELECT log_mode FROM v$database;

-- If NOARCHIVELOG:
SHUTDOWN IMMEDIATE;
STARTUP MOUNT;
ALTER DATABASE ARCHIVELOG;
ALTER DATABASE OPEN;

-- Force logging
ALTER DATABASE FORCE LOGGING;
ALTER SYSTEM SWITCH LOGFILE;

1.2 Create Standby Redo Logs (SRLs)

Create online redo groups + 1 SRL per thread & size ≥ largest ORL.

-- OMF environment
ALTER DATABASE ADD STANDBY LOGFILE THREAD 1 GROUP 10 SIZE 200M;
ALTER DATABASE ADD STANDBY LOGFILE THREAD 1 GROUP 11 SIZE 200M;
ALTER DATABASE ADD STANDBY LOGFILE THREAD 1 GROUP 12 SIZE 200M;
ALTER DATABASE ADD STANDBY LOGFILE THREAD 1 GROUP 13 SIZE 200M;

-- Non‑OMF (explicit paths)
ALTER DATABASE ADD STANDBY LOGFILE THREAD 1 GROUP 10 ('/u01/oradata/cdb1/standby_redo01.log') SIZE 200M;
...

1.3 Key Initialization Parameters

SHOW PARAMETER db_name;         -- MYDBPROD
SHOW PARAMETER db_unique_name; -- MYDBPROD

ALTER SYSTEM SET standby_file_management = AUTO;

2 – Network Configuration

2.1 TNS Entries (both servers)

MYDBPROD =
  (DESCRIPTION =
    (ADDRESS = (PROTOCOL = TCP)(HOST = oracle1.localdomain)(PORT = 1521))
    (CONNECT_DATA = (SID = MYDBPROD))
  )

MYDBDG =
  (DESCRIPTION =
    (ADDRESS = (PROTOCOL = TCP)(HOST = oracle2.localdomain)(PORT = 1521))
    (CONNECT_DATA = (SID = MYDBPROD))
  )

2.2 Listener Configuration

Add a static SID entry for the broker (_DGMGRL) on both servers, then restart the listener.

lsnrctl stop
lsnrctl start

3 – Standby Server Preparation

1. Create /tmp/initMYDBDG.ora with:
   *.db_name='MYDBPROD'
2. Create directories:

   mkdir -p /u02/oradatatest/MYDBDG
   mkdir -p /u02/archivelog/MYDBDG
   mkdir -p /u01/app/oracle/admin/MYDBDG/adump
   mkdir -p /u02/fra

3. Copy (or create) password file:
   orapwd file=$ORACLE_HOME/dbs/orapwMYDBPROD password=<pwd> entries=10

4 – RMAN Duplicate (Active)

4.1 Start Auxiliary Instance

export ORACLE_SID=MYDBPROD
sqlplus / as sysdba <<EOF
  STARTUP NOMOUNT PFILE='/tmp/initMYDBDG.ora';
EOF

4.2 Run Duplicate

rman TARGET sys@MYDBPROD AUXILIARY sys@MYDBDG

RUN {
DUPLICATE TARGET DATABASE
  FOR STANDBY
  FROM ACTIVE DATABASE
  DORECOVER
  SPFILE
    SET db_unique_name='MYDBDG'
    SET audit_file_dest='/u01/app/oracle/admin/MYDBDG/adump'
    SET db_file_name_convert='/u02/oradata/MYDBPROD','/u02/oradatatest/MYDBDG'
    SET log_file_name_convert='/u02/oradata/MYDBPROD','/u02/oradatatest/MYDBDG'
    SET log_archive_dest_1='LOCATION=USE_DB_RECOVERY_FILE_DEST VALID_FOR=(ALL_LOGFILES,ALL_ROLES) DB_UNIQUE_NAME=MYDBDG'
    SET db_recovery_file_dest='/u02/fra'
    SET db_recovery_file_dest_size='100G'
    SET job_queue_processes='0'
  NOFILENAMECHECK;
}

5 – Enable Data Guard Broker

-- On both databases
ALTER SYSTEM SET dg_broker_start = TRUE;

-- On primary
DGMGRL sys@MYDBPROD
CREATE CONFIGURATION my_dg_config AS
  PRIMARY DATABASE IS MYDBPROD \
  CONNECT IDENTIFIER IS MYDBPROD;
ADD DATABASE MYDBDG AS CONNECT IDENTIFIER IS MYDBDG;
ENABLE CONFIGURATION;

-- Quick status
SHOW CONFIGURATION;
SHOW DATABASE MYDBDG;

6 – Broker Operations

6.1 Start / Stop Apply & Transport

-- Apply (standby)
EDIT DATABASE 'MYDBDG' SET STATE='APPLY-OFF';
EDIT DATABASE 'MYDBDG' SET STATE='APPLY-ON';

-- Transport (primary)
EDIT DATABASE 'MYDBPROD' SET STATE='TRANSPORT-OFF';
EDIT DATABASE 'MYDBPROD' SET STATE='TRANSPORT-ON';

Classic SQL equivalents:

ALTER DATABASE RECOVER MANAGED STANDBY DATABASE CANCEL;
ALTER DATABASE RECOVER MANAGED STANDBY DATABASE USING CURRENT LOGFILE DISCONNECT;

6.2 Switchover Example

DGMGRL> SWITCHOVER TO MYDBDG;  -- make standby primary
DGMGRL> SWITCHOVER TO MYDBPROD; -- switch back

6.3 Failover & Re‑instate

DGMGRL> FAILOVER TO MYDBDG;
-- New primary: MYDBDG

DGMGRL> REINSTATE DATABASE MYDBPROD;  -- requires Flashback ON

7 – Flashback Database

Ensure FRA is configured (db_recovery_file_dest & _size) then:

ALTER DATABASE FLASHBACK ON;           -- primary
ALTER DATABASE RECOVER MANAGED STANDBY DATABASE CANCEL;
ALTER DATABASE FLASHBACK ON;           -- standby
ALTER DATABASE RECOVER MANAGED STANDBY DATABASE USING CURRENT LOGFILE DISCONNECT;

7 – Preventing Timeouts Because Of Firewall

Ensure that your sqlnet.ora file does include SQL_NET.EXPIRE_TIME parameter to a couple of minutes just to keep the connection alive. Some enviornments might cause timeouts.

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🎉 That’s it! Your Oracle 19c Data Guard environment is ready for real‑time apply, switchover & failover testing.