During peak business hours, It is not advised to export data from production .(as it might impact the performance).
So if we have a physical standby database, we can export data using datapump from standby database.

PRE-REQUISITES:

1. Physical standby database should be in READ-ONLY MODE (ACTIVE DATAGUARD)
2.We cannot run expdp directly on physical standby database. Because datapump job can be created only on a read-write database(OPEN).
So to achieve this, we will use the NETWORK_LINK parameter and run the expdp job from any non-standby database(OPEN database)

 

Refer open physical standby database in read only mode 

STEPS:

1. Check whether standby database is in read only mode:

2. create a database link on non standby database.[POINTING TO STANDBY DB]

3. Create db directory on non-standby server:

4. Run expdp from non-standby database server:

We have successfully generated the export dump from standby database.