Oracle Physical Standby

 Oracle Physical Standby

 

In Oracle, a physical standby database is a type of standby database that maintains an exact copy of the primary database by continuously applying redo data from the primary database. It serves as a failover solution and provides high availability and data protection.

Here are key points to understand about a physical standby database in Oracle:

1. Data Synchronization: The physical standby database stays synchronized with the primary database by receiving and applying redo data, which contains all the changes made to the primary database. Redo data is shipped from the primary database and applied to the physical standby database using redo apply technology.

2. Data Protection: The physical standby database provides data protection by maintaining a synchronized copy of the primary database. In the event of a primary database failure, the physical standby database can be quickly activated to take over as the new primary database, minimizing downtime and data loss.

3. Continuous Redo Apply: The physical standby database continuously applies redo data received from the primary database, keeping the standby database up-to-date. Redo apply applies the changes to the standby database's data files, ensuring they mirror the primary database's data.

4. Read-Only Access: In addition to serving as a failover solution, the physical standby database can also be used for read-only reporting or offloading backup activities. This is possible because the standby database is an exact replica of the primary database.

5. Managed Recovery Process (MRP): The Managed Recovery Process (MRP) is the background process responsible for applying redo data to the physical standby database. It continuously runs on the standby database and applies redo data as it is received, keeping the standby database synchronized.

6. Data Guard: Oracle Data Guard is the primary technology used to configure and manage physical standby databases. It provides various features and options to ensure data synchronization, automatic failover, and management of the standby database.

7. Switchover and Failover: Switchover is the planned transition from the primary database to the standby database, where roles are reversed. Failover is the unplanned transition that occurs when the primary database becomes unavailable, and the standby database takes over as the new primary database.

By implementing a physical standby database, organizations can achieve high availability and data protection, ensuring that their critical Oracle databases remain accessible and their data remains safe in the event of primary database failures.