Configure DataGuard broker 19c

Oracle Data Guard Broker provides a centralized framework to manage and monitor an entire Data Guard configuration through a unified client interface. The broker simplifies complex administrative tasks, automates failover operations, and ensures configuration consistency across all databases in your Data Guard environment.

Data Guard Broker Overview
Architecture and Configuration Files
Key Benefits and Capabilities
Prerequisites
Removing Existing Broker Configuration
Disabling Archive Destinations
Enabling Data Guard Broker
Creating Broker Configuration
Enabling and Verifying Configuration
Configuration Management

Data Guard Broker Overview

Data Guard Broker is Oracle’s enterprise-class management layer that sits above the core Data Guard infrastructure. It provides a unified interface for managing complex Data Guard topologies with multiple standby databases, automating routine tasks, and ensuring configuration consistency.

What is Data Guard Broker?

Centralized Management Framework: Manage entire Data Guard configurations through a single client connection to any database in the configuration
Command-Line Interface (DGMGRL) : Powerful CLI for configuration, monitoring, and management operations
Automated Operations : Simplifies switchover and failover with single-command execution
Unified Configuration : Eliminates the need for multiple SQL*Plus sessions across different databases
Configuration Persistence : Maintains configuration details in binary flat files stored at each database location

Broker Limitations

DGMGRL (Command Line Interface) does not have the ability to create standby databases from scratch. Use RMAN Active Duplicate or Oracle Enterprise Manager Cloud Control GUI for standby database creation. The CLI is primarily used for configuration management and operational tasks after standby databases are established.

Architecture and Configuration Files

Configuration File Storage

The broker maintains its configuration metadata in binary flat files rather than within the database itself. This design ensures that configuration information remains accessible even when databases are not mounted or open.

Configuration File Parameters

Two initialization parameters control the location of broker configuration files:

DG_BROKER_CONFIG_FILE1 – Primary configuration file location
DG_BROKER_CONFIG_FILE2 – Secondary configuration file location (redundancy)

🔒 Redundancy and Protection Two copies of the configuration files are always maintained on each database node for redundancy and protection against corruption. If one file becomes corrupted, the broker automatically uses the alternate file. Both files are stored in ASM disk groups or on the local filesystem depending on your storage architecture.

File Location Examples

SQL> SHOW PARAMETER dg_broker_config

NAME TYPE VALUE
———————————— ———– ———————-——————-—–——————-————-

dg_broker_config_file1 string +DATA/woravr/dr1woravr.dat
dg_broker_config_file2 string +DATA/woravr/dr2woravr.dat

Key Benefits and Capabilities

Simplified Switchover/Failover

Execute role transitions with a single command, minimizing downtime associated with planned maintenance or unplanned outages. The broker performs all pre-checks and validation automatically.

Unified Configuration Management

Replace multiple SQL*Plus statements across different databases with a single unified interface. All configuration changes are automatically propagated to all members.

Automated Monitoring

Continuous health monitoring of all databases in the configuration with automatic detection of lag, apply rate issues, and connectivity problems.

Fast-Start Failover

Optional automatic failover capability that detects primary database failures and initiates failover to a designated standby database without manual intervention.

Configuration Validation

Performs comprehensive pre-checks before role transitions to ensure all prerequisites are met, reducing the risk of failed switchover or failover operations.

Centralized Property Management

Manage Data Guard-related initialization parameters through broker properties, ensuring consistency across all databases in the configuration.

Prerequisites

Before configuring Data Guard Broker, ensure the following conditions are met:

Data Guard Configuration: A functioning Data Guard configuration with at least one standby database
Network Connectivity: TNS connectivity established between all databases in the configuration
Matching Software Versions: All databases running the same Oracle Database version
Unique DB_UNIQUE_NAME: Each database must have a unique DB_UNIQUE_NAME parameter
Compatible Parameter: The COMPATIBLE parameter should be set consistently across all databases
Valid TNS Entries: Properly configured tnsnames.ora entries on all nodes

Step 1: Removing Existing Broker Configuration

If you have an existing broker configuration that needs to be reconfigured or removed, start by cleanly removing the current configuration.

1. Connect to DGMGRL and Remove Configuration

[oracle@west01 ~]$ dgmgrl 

DGMGRL for Linux: Release 19.0.0.0.0 - Production on Tue Apr 20 15:51:38 2021 
Version 19.3.0.0.0 

Copyright (c) 1982, 2019, Oracle and/or its affiliates.  All rights reserved. 

Welcome to DGMGRL, type "help" for information. 

DGMGRL> remove configuration; 
Removed configuration 

DGMGRL> show configuration; 
ORA-16532: Oracle Data Guard broker configuration does not exist 

Configuration details cannot be determined by DGMGRL

Configuration Removal Impact Removing the broker configuration does not affect the underlying Data Guard setup. Redo transport and apply services continue to function. Only the broker metadata is removed, and you can recreate the broker configuration at any time.

Step 2: Disabling LOG_ARCHIVE_DEST_2
Before enabling Data Guard Broker, clear the LOG_ARCHIVE_DEST_2 parameter on both primary and standby databases. The broker will manage this parameter automatically once enabled.

Disable on Primary Database

2Clear Archive Destination on Primary 

SQL> SHOW PARAMETER log_archive_dest_2 

NAME                                 TYPE        VALUE                          
------------------------------------ ----------- ----------------- 
log_archive_dest_2                   string      SERVICE=woravrdr LGWR ASYNC 
                                                  VALID_FOR=(ONLINE_LOGFILES, 
                                                  PRIMARY_ROLE) 
                                                  DB_UNIQUE_NAME=woravrdr 

SQL> ALTER SYSTEM SET LOG_ARCHIVE_DEST_2='' SCOPE=BOTH; 

System altered. 

SQL> SHOW PARAMETER log_archive_dest_2 

NAME                                 TYPE        VALUE 
------------------------------------ ----------- ----------------- 
log_archive_dest_2                   string

Disable on Standby Database

3. Clear Archive Destination on Standby


SQL> SHOW PARAMETER log_archive_dest_2 

NAME                                 TYPE        VALUE 
------------------------------------ ----------- ----------------- 
log_archive_dest_2                   string      SERVICE=woravr LGWR ASYNC 
                                                  VALID_FOR=(ONLINE_LOGFILES, 
                                                  PRIMARY_ROLE) 
                                                  DB_UNIQUE_NAME=woravr 

SQL> ALTER SYSTEM SET LOG_ARCHIVE_DEST_2='' SCOPE=BOTH; 

System altered. 

SQL> SHOW PARAMETER log_archive_dest_2 

NAME                                 TYPE        VALUE 
------------------------------------ ----------- ----------------- 
log_archive_dest_2                   string

💡 Why Clear LOG_ARCHIVE_DEST_2? The broker automatically manages redo transport destinations through its own property system. Manually configured LOG_ARCHIVE_DEST parameters can conflict with broker-managed settings. Once the broker is enabled, it will configure these parameters according to your broker properties.

Step 3: Enabling Data Guard Broker
The DG_BROKER_START parameter controls whether the Data Guard Broker is active on each database. This must be set to TRUE on all databases that will participate in the broker configuration.

Enable Broker on Primary Database

4. Enable DG Broker Process on Primary

SQL> SHOW PARAMETER dg_broker_start 

NAME                                 TYPE        VALUE 
------------------------------------ ----------- ----------------- 
dg_broker_start                      boolean     TRUE 

-- If not already TRUE, reset the broker process 

SQL> ALTER SYSTEM SET dg_broker_start=FALSE SCOPE=BOTH; 

System altered. 

SQL> ALTER SYSTEM SET dg_broker_start=TRUE SCOPE=BOTH; 

System altered. 

SQL> SHOW PARAMETER dg_broker_start 

NAME                                 TYPE        VALUE 
------------------------------------ ----------- ----------------- 
dg_broker_start                      boolean     TRUE

Enable Broker on Standby Database
5. Enable DG Broker Process on Standby

SQL> SHOW PARAMETER dg_broker_start 

NAME                                 TYPE        VALUE 
------------------------------------ ----------- ----------------- 
dg_broker_start                      boolean     TRUE 

-- If not already TRUE, reset the broker process 

SQL> ALTER SYSTEM SET dg_broker_start=FALSE SCOPE=BOTH; 

System altered. 

SQL> ALTER SYSTEM SET dg_broker_start=TRUE SCOPE=BOTH; 

System altered. 

SQL> SHOW PARAMETER dg_broker_start 

NAME                                 TYPE        VALUE 
------------------------------------ ----------- ----------------- 
dg_broker_start                      boolean     TRUE

🔄 Broker Process Startup When DG_BROKER_START is set to TRUE, Oracle starts the Data Guard Broker monitor process (DMON) which manages the broker configuration and handles monitoring tasks. This process runs independently on each database instance.

Step 4: Creating Data Guard Broker Configuration
Connect to DGMGRL and create a new broker configuration. The configuration is named and includes the primary database as the initial member. 6Connect to DGMGRL on Primary Database

[oracle@west01 ~]$ dgmgrl 

DGMGRL for Linux: Release 19.0.0.0.0 - Production on Tue Apr 20 15:51:38 2021 
Version 19.3.0.0.0 

Copyright (c) 1982, 2019, Oracle and/or its affiliates.  All rights reserved. 

Welcome to DGMGRL, type "help" for information. 

DGMGRL> connect / 
Connected to "woravr" 
Connected as SYSDG.

💡 Authentication Options

connect / – Uses operating system authentication (requires DBA group membership)
connect sys/password@tns_name as sysdg – Uses password authentication

SYSDG role provides Data Guard administrative privileges

Create Broker Configuration with Primary Database

7. Create Configuration and Add Primary

DGMGRL> create configuration 'woravr' as 
        primary database is 'woravr' 
        connect identifier is woravr; 

Configuration "woravr" created with primary database "woravr"

Add Standby Database to Configuration

8. Add Physical Standby Database

DGMGRL> add database 'woravrdr' as 
        connect identifier is woravrdr 
        maintained as physical; 

Database "woravrdr" added

Verify Configuration Creation

9. Display Configuration Status

DGMGRL> show configuration; 

Configuration - woravr 

Protection Mode: MaxPerformance 
   Members: 
   woravr    - Primary database 
   woravrdr  - Physical standby database 

Fast-Start Failover: DISABLED 

Configuration Status: 
DISABLED

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Ut elit tellus, luctus nec ullamcorper mattis, pulvinar dapibus leo.

Configuration Not Yet Active At this stage, the configuration exists but is not yet enabled. The DISABLED status means the broker is not actively managing the Data Guard environment. You must explicitly enable the configuration for the broker to take control.

Step 5: Enabling and Verifying Configuration

Reconfigure Archive Destinations

Before enabling the broker configuration, ensure that LOG_ARCHIVE_CONFIG and LOG_ARCHIVE_DEST_2 are properly configured on both databases.

10. Configure Archive Parameters on Primary

SQL> ALTER SYSTEM SET LOG_ARCHIVE_CONFIG= 
      'DG_CONFIG=(woravr,woravrdr)' 
      SCOPE=BOTH; 

System altered. 

SQL> ALTER SYSTEM SET LOG_ARCHIVE_DEST_2= 
      'SERVICE=woravrdr LGWR ASYNC 
       VALID_FOR=(ONLINE_LOGFILES,PRIMARY_ROLE) 
       DB_UNIQUE_NAME=woravrdr' 
      SCOPE=BOTH; 

System altered.

11. Configure Archive Parameters on Standby

SQL> ALTER SYSTEM SET LOG_ARCHIVE_CONFIG= 
      'DG_CONFIG=(woravr,woravrdr)' 
      SCOPE=BOTH; 

System altered. 

SQL> ALTER SYSTEM SET LOG_ARCHIVE_DEST_2= 
      'SERVICE=woravr LGWR ASYNC 
       VALID_FOR=(ONLINE_LOGFILES,PRIMARY_ROLE) 
       DB_UNIQUE_NAME=woravr' 
      SCOPE=BOTH; 

System altered.

Enable the Broker Configuration

12. Activate Broker Management .

DGMGRL> enable configuration; 

Enabled

Verify Configuration Status

13. Check Configuration Health

DGMGRL> show configuration; 

Configuration - woravr 

Protection Mode: MaxPerformance 
   Members: 
   woravr    - Primary database 
   woravrdr  - Physical standby database 

Fast-Start Failover: DISABLED 

Configuration Status: 
SUCCESS   (status updated 6 seconds ago)

✅ Configuration Successfully Enabled The SUCCESS status confirms that the broker configuration is active and all databases are communicating properly. The broker is now managing the Data Guard environment. Display Detailed Standby Database Status
14. View Standby Database Details

DGMGRL> show database 'woravrdr'; 

Database - woravrdr 

Role:               PHYSICAL STANDBY 
   Intended State:     APPLY-ON 
   Transport Lag:      0 seconds (computed 0 seconds ago) 
   Apply Lag:          0 seconds (computed 0 seconds ago) 
   Average Apply Rate: 6.00 KByte/s 
   Real Time Query:    OFF 
   Instance(s): 
     woravrdr1 
     woravrdr2 

Database Status: 
SUCCESS

Status Interpretation

Transport Lag: 0 seconds – Redo is being shipped in real-time
Apply Lag: 0 seconds – Standby is fully synchronized with primary
Intended State: APPLY-ON – Managed recovery is active
Database Status: SUCCESS – No errors or warnings detected

Configuration Management Commands

Common DGMGRL Operations

Operation	Command	Purpose
Show Configuration	SHOW CONFIGURATION;	Display overall configuration status
Show Database	SHOW DATABASE ‘db_name’;	Display detailed database information
Validate Configuration	VALIDATE DATABASE ‘db_name’;	Check database readiness for role transition
Switchover	SWITCHOVER TO ‘standby_name’;	Perform planned role reversal
Failover	FAILOVER TO ‘standby_name’;	Perform emergency failover
Disable Database	DISABLE DATABASE ‘db_name’;	Temporarily remove database from management
Enable Database	ENABLE DATABASE ‘db_name’;	Resume management of database
Edit Property	EDIT DATABASE ‘db_name’ SET PROPERTY…	Modify database-level properties
Remove Database	REMOVE DATABASE ‘db_name’;	Remove database from configuration
Reinstate Database	REINSTATE DATABASE ‘db_name’;	Reconnect failed primary as standby

Useful Property Management

Display Database Properties

DGMGRL> show database 'woravrdr' LogXptMode; 

  LogXptMode = 'ASYNC' 

DGMGRL> show database 'woravrdr' ApplyLagThreshold; 

  ApplyLagThreshold = '30'

Modify Database Properties

-- Change redo transport mode to synchronous 
DGMGRL> edit database 'woravrdr' set property LogXptMode='SYNC'; 

Property "LogXptMode" updated 

-- Enable Active Data Guard (read-only standby) 
DGMGRL> edit database 'woravrdr' set state='APPLY-ON' with REAL TIME APPLY; 

Succeeded.

Performing a Switchover Operation

Validate Switchover Readiness

DGMGRL> validate database 'woravrdr'; 

  Database Role:     Physical standby database 
   Primary Database:  woravr 

Ready for Switchover:  Yes 
   Ready for Failover:    Yes (Primary Running) 

Managed by Clusterware: 
     woravr:   YES 
     woravrdr: YES 

Validating static connect identifier for the primary database woravr... 
   The static connect identifier allows for a connection to database "woravr".

Execute Switchover

DGMGRL> switchover to 'woravrdr'; 

Performing switchover NOW, please wait... 
Operation requires a connection to database "woravrdr" 
Connecting ... 
Connected to "woravrdr" 
Connected as SYSDG. 
New primary database "woravrdr" is opening... 
Operation requires start up of instance "woravr1" on database "woravr" 
Starting instance "woravr1"... 
Connected to an idle instance. 
ORACLE instance started. 
Connected to "woravr" 
Database mounted. 
Database opened. 
Connected to "woravr" 
Switchover succeeded, new primary is "woravrdr"

✅ Switchover Complete The broker has successfully reversed the roles. The former standby database (woravrdr) is now the primary, and the former primary (woravr) is now functioning as a physical standby. All redo transport and apply services are automatically reconfigured.

Protection Mode Management

Data Guard supports three protection modes that define the level of data protection:

Maximum Performance: Default mode, provides best performance with minimal impact to primary
Maximum Availability: Ensures zero data loss under normal conditions while maintaining high availability
Maximum Protection: Guarantees zero data loss but primary shuts down if synchronous standby is unavailable

-- Change protection mode to Maximum Availability 
DGMGRL> edit configuration set protection mode as maxavailability; 

Succeeded. 

-- Change protection mode to Maximum Protection 
DGMGRL> edit configuration set protection mode as maxprotection; 

Succeeded. 

-- Return to Maximum Performance 
DGMGRL> edit configuration set protection mode as maxperformance; 

Succeeded.

🚨 Protection Mode Prerequisites

Maximum Availability and Maximum Protection require SYNC or FASTSYNC redo transport mode
Standby redo logs must be configured on all standby databases
Network bandwidth must be adequate to support synchronous redo transmission
Maximum Protection mode can cause primary database shutdown if synchronous standby becomes unavailable

Fast-Start Failover Configuration

Fast-Start Failover (FSFO) enables automatic failover when the primary database becomes unavailable. This requires an observer process and careful configuration.

-- Enable Fast-Start Failover 
DGMGRL> enable fast_start failover; 

Enabled. 

-- Start Observer (run in separate session) 
DGMGRL> start observer; 

Observer started 

-- Check FSFO status 
DGMGRL> show fast_start failover; 

Fast-Start Failover:  Enabled 

Protection Mode:      MaxPerformance 
   Lag Limit:            30 seconds 

Threshold:            30 seconds 
   Active Target:        woravrdr 
   Potential Targets:    "woravrdr" 
   Observer:             west01 
   Shutdown Primary:     TRUE 
   Auto-reinstate:       TRUE 

Configurable Failover Conditions 
   Health Conditions: 
     Corrupted Controlfile          YES 
     Corrupted Dictionary           YES 
     Inaccessible Logfile            NO 
     Stuck Archiver                  NO 
     Datafile Write Errors          YES 

Oracle Error Conditions: 
     (none)

FSFO ConsiderationsFast-Start Failover requires careful planning and testing. The observer process must run on a separate host from both primary and standby databases. Ensure network connectivity between observer and all databases is reliable. Test FSFO behavior in non-production environments before enabling in production.
✅ Data Guard Broker Configuration Complete Your Oracle Data Guard Broker is now fully configured and operational. You can manage your entire Data Guard environment through the centralized DGMGRL interface, perform switchovers with single commands, and optionally enable Fast-Start Failover for automatic failover capabilities. The broker provides comprehensive monitoring and ensures configuration consistency across all

Step 2: Disabling LOG_ARCHIVE_DEST_2

Step 3: Enabling Data Guard Broker

Enable Broker on Standby Database

Step 4: Creating Data Guard Broker Configuration

Configuration Management Commands

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