Oracle Data Guard and Active Data Guard… Both are super cool solutions for high availability and disaster recovery solutions. However, they differ in terms of their capabilities and functionalities.

You need to be Enterprise Edition version to can use Data Guard. Just reminder, Oracle Data Guard bundle with Oracle EE license. You need to license Active Data Guard.

So as I said, Oracle Data Guard and Active Data Guard are both features of Oracle Database that provide high availability and disaster recovery solutions. However, they differ in terms of their capabilities and functionalities.

Lets dig in this topic

Oracle Data Guard:
Oracle Data Guard is a feature that enables the creation, maintenance, and monitoring of standby databases for disaster recovery purposes. It provides a set of tools and technologies to create and manage a standby database that can be used for failover in case of primary database failure. The primary database continuously sends its redo data to the standby database, which keeps it synchronized and ready to take over in case of a failure. Data Guard operates in a “standby mode,” where the standby database is available for read-only access but not for active transactions.

Key features of Oracle Data Guard include:

Physical Standby Database: It maintains an identical copy of the primary database at the block level.

Logical Standby Database: It maintains a synchronized copy of the primary database at the logical level, allowing additional flexibility for reporting and data manipulation.

Fast-Start Failover: It enables automatic failover to the standby database in the event of a failure in the primary database.

Redo Apply: It continuously applies the redo data received from the primary database to keep the standby database synchronized.

Active Data Guard:
Active Data Guard is an extension of Oracle Data Guard and provides additional capabilities to offload read-intensive workloads to the standby database. Unlike Data Guard, Active Data Guard allows read and write access to the standby database, enabling active transactions and real-time reporting on the standby system. This feature enhances the utilization of the standby system, making it an active part of the overall database infrastructure.

Key features of Active Data Guard include:

Real-Time Query: It enables executing queries on the standby database while maintaining real-time data synchronization with the primary database.

Automatic Block Repair: It automatically detects and repairs corrupt data blocks on the standby database.

Far Sync: It allows the creation of a remote standby database that acts as a buffer for redo data, reducing the network overhead between the primary and standby databases.

Online Rolling Upgrades: It allows upgrading the Oracle Database version of the primary and standby databases without downtime.

In summary, Oracle Data Guard focuses on providing disaster recovery capabilities by maintaining synchronized standby databases, while Active Data Guard extends this functionality by allowing read and write access to the standby database, enabling real-time querying and offloading read-intensive workloads.