What does Active Data Guard mean?

Active Data Guard is a comprehensive solution to eliminate single points of failure for mission critical Oracle Databases. It prevents data loss and downtime simply and economically by maintaining a synchronized physical replica (standby) of a production database (primary).

How do I enable Active Data Guard in physical standby database?

Perform the following steps:
  1. Invoke DGMGRL and connect as SYS. Enter <your password> for SYS. …
  2. Invoke SQL*Plus and connect to your standby database as SYSDBA. …
  3. Invoke DGMGRL and connect as SYS. …
  4. Invoke SQL*Plus and connect to your standby database as SYSDBA. …
  5. Invoke SQL*Plus and connect to your primary database as SYSDBA.

How is Active Data Guard license?

Data Guard is a feature of the Oracle Database Enterprise Edition itself and does not require separate licensing. On the other hand, Active Data Guard is a so-called Oracle Database Enterprise Edition Option and as such requires separate licensing.

How do I know if my Active Data Guard is enabled?

If you start a database in SQL*Plus using the STARTUP command and then invoke managed recovery, the Active Data Guard will be enabled.

What is the difference between physical standby and logical standby?

The logical standby database is a database that does not have the schema structure exactly similar to the source database. In contrast, a physical standby database is a database that replicates the exact contents of its primary database across the Oracle Net Network layer.

How do I know if my database is primary or standby?

You can use the DGMGRL show configuration and show database database_name commands to confirm the Data Guard Standby database configuration before enabling a standby database. Here is how you enable your primary and standby databases using the DGMGRL command: DGMGRL> enable configuration; Enabled.

How do I know if Data Guard is running?

To determine if real-time apply is enabled, query the RECOVERY_MODE column of the V$ARCHIVE_DEST_STATUS view. SELECT RECOVERY_MODE FROM V$ARCHIVE_DEST_STATUS; The V$DATAGUARD_STATUS fixed view displays events that would typically be triggered by any message to the alert log or server process trace files.

How do I turn off Active Data Guard?

Official Oracle support notice: “There is no way to disable ADG, just prevent its usage by ensuring the physical standby database is always mounted when Media Recovery (MRP) runs“.

How do I open physical standby database in read only mode?

To open a standby database for read-only access when it is currently shut down:
  1. Start the Oracle instance for the standby database without mounting it: SQL> STARTUP NOMOUNT;
  2. Mount the standby database: SQL> ALTER DATABASE MOUNT STANDBY DATABASE;
  3. Open the database for read-only access: SQL> ALTER DATABASE OPEN READ ONLY;

What is Data Guard lag apply?

APPLY LAG – Apply lag is a measure of the degree to which the data in a standby database lags behind the data in the primary database, due to delays in propagating and applying redo to the standby database.

How can I speed up my MRP?

Increasing MRP apply speed in Dataguard broker
  1. Start MRP process with number of parallel process. ALTER DATABASE RECOVER MANAGED STANDBY DATABASE PARALLEL <no of process> DISCONNECT FROM SESSION;
  2. Now check the MRP Active apply speed.

What is MRP process in Data Guard?

The managed recovery process (MRP) applies information from the archived redo logs to the standby database. When performing managed recovery operations, log apply services automatically apply archived redo logs to maintain transactional synchronization with the primary database.

What is the purpose of standby redo logs?

Standby redo logs are used to store data received from another database or the primary data source. Standby redo logs are present at the destination database end.