Architecture

Data Guard provides the management, monitoring, and automation software to create and maintain one or more synchronized copies of a production database to protect Oracle data from failures, disasters, human error, and data corruptions while providing high availability for mission critical applications. Data Guard is included with Oracle Database Enterprise Edition.

Functionality

Active Data Guard is licensed option to the  Oracle Database Enterprise Edition and enables advanced capabilities that extend the basic Data Guard functionality.  These capabilities include:

• Real-Time Query and DML Offload uses the standby database for queries, reports and occasional updates without impacting protection of the primary. 
   

• Automatic Block Repair provides an automatic and user-transparent recovery of corrupted database blocks from either the primary or the standby database. 
   

• Standby Block Change Tracking enables incremental backups on the standby. 
   

• Far Sync enables zero data loss protection across any distance.
   

• Global Data Services load balance connection requests and provide an integrated service management across replicated databases, considering placement of connections depending on read or read/write workload. 
   

• Application Continuity makes outages transparent to application users.