Data Guard Benefits
Disaster recovery and high availability
Data Guard provides an efficient and comprehensive disaster recovery and high availability solution. Automatic fail over and easy-to-manage switch over capabilities allow quick role reversals between primary and standby databases, minimizing the downtime of the primary database for planned and unplanned outages.
Complete data protection
A standby database also provides an effective safeguard against data corruptions and user errors. Storage level physical corruptions on the primary database do not propagate to the standby database. Similarly, logical corruptions or user errors that cause the primary database to be permanently damaged can be resolved. Finally, the redo data is validated at the time it is received at the standby database and further when applied to the standby database.
Efficient utilization of system resources
A physical standby database can be used for backups and read-only reporting, thereby reducing the primary database workload and saving valuable CPU and I/O cycles. In Oracle Database 10g Release 2, a physical standby database can also be easily converted back and forth between being a physical standby database and an open read/write database. A logical standby database allows its tables to be simultaneously available for read-only access while they are updated from the primary database. A logical standby database also allows users to perform data manipulation operations on tables that are not updated from the primary database. Finally, additional indexes and materialized views can be created in the logical standby database for better reporting performance.
Protection from communication failures
If network connectivity is lost between the primary and one or more standby databases, redo data cannot be sent from the primary to those standby databases. Once connectivity is re-established, the missing redo data is automatically detected by Data Guard and the necessary archive logs are automatically transmitted to the standby databases. The standby databases are resynchronized with the primary database, with no manual intervention by the administrator.
Centralized and simple management
Data Guard Broker automates the management and monitoring tasks across the multiple databases in a Data Guard configuration. Administrators may use either Oracle Enterprise Manager or the Broker’s own specialized command-line interface (DGMGRL) to take advantage of this integrated management framework.