Sunday, May 5, 2019

Restoring and Recovering Files over Network in Oracle

Oracle 12c offers many new features and restoring, recovering files over the network is one of the new feature. Using RMAN you can restore and recover a database, datafile, controlfile, tablespace or spfile over the network from a physical standby database. To restore the database over the network, use the RESTORE… FROM SERVICE command and use the RECOVER…FROM SERVICE command to recover the database over the network. The FROM SERVICE clause specifies the service name of the physical standby.

You can also use multisection, compression and encryption to improve backup and restore performance.

  • Use SECTION SIZE with RESTORE command to perform multisection restore
  • Use SET ENCRYPTION clause before the RESTORE command to specify the encryption
  • Use USING COMPRESSED BACKUPSET clause to compress backup sets
This feature is useful to synchronize primary and standby database. Here are the few scenarios
Roll-forward a physical standby database to sync with the primary database
Restore the primary database using physical standby database.
Restore physical standby database using the primary database.

In the following example restoring data file over the network from physical standby to primary database

Connected to primary database implicitly

Restoring the datafile on the primary using datafile on physical database with service “standby_db”
RMAN> RESTORE DATAFILE '/oradata1/orcl/users.dbf' FROM SERVICE standby_db SECTION SIZE 1024M;

Prior to 12c , to restore and recover files over the network, you need to use RMAN BACKUP INCREMENTAL FROM SCN command to create a backup on the primary database that started at the current SCN of the standby, and was then used to roll the standby database forward in time. That manual, multi-step method is not necessary as of Oracle Database 12c.

Satishbabu Gunukula, Oracle ACE