The Data Guard broker is a utility provided with the Oracle database server of the Enterprise edition. It includes the functionality to manage standby databases. It is also an integral part of Data Guard and of Oracle's Database Enterprise Manager. Broker interfaces are instinctive and easy, allowing for centralized control of the Data Guard configuration that makes the Data Guard an enhanced high availability and disaster protection solution. The Data Guard broker makes it easy to maintain and administer several standby databases. It maintains its own configuration files and runs a background process Data Guard Monitor Process (DMON) on both primary and standby database servers.

The Oracle Data Guard broker was introduced in the 9i Release 2, but the Oracle Database 11g version introduced several enhancements to the Data Guard broker feature so that a DBA could easily manage a complex and multidatabase disaster recovery environment.

The Data Guard broker consolidates the setup, upkeep, and monitoring of Data Guard configurations. The Data Guard broker when used with the Enterprise Manager becomes a powerful tool, offering configuration, monitoring, alerts, performance analysis, easy switchovers, and automatic failovers.

The Data Guard Monitor (DMON) process and configuration file resides on the server side. However the Oracle Data Guard broker can be managed by DGMGRL or OEM from the client side as well. The Data Guard broker can be configured on existing or new standby databases and on either physical or logical standby databases.

The Data Guard broker is an additional utility of the standby database that makes the maintenance and administration of several standby databases at once much easier. The Data Guard broker uses its own background process (DMON) on each primary and standby database and its own configuration file for interaction. The DMON process is started if you set the initialization parameter DG_BROKER_START to TRUE. This parameter is a dynamic parameter, and you can set it to TRUE or FALSE without any database bounce. To create and maintain the configuration files, you need to create a Data Guard configuration using either the Data Guard wizard from Cloud Control or you need to create it manually via the command-line DGMGRL.

The Data Guard broker framework facilitates the configuration and setup of Data Guard, monitors the redo log transport, and monitors the log apply services. It also helps in Data Guard operating tasks, such as switchovers, failovers, fast-start failovers, and reinstating the primary database. This can be better illustrated with the following diagram: