Can anyone explain to me what is the difference between “Duplicate” and “Restore out of place” for oracle databases? Isn’t it the same thing? It does restore data from a specific backup to a specific server/oracle instance. I still can’t undestand when to use one option over the other. Thanks to anyone that can explain.
Difference between oracle duplicate and restore out of place
Best answer by Gowri Shankar
Hi
For duplicate DB, we rely on the oracle duplicate database functionality which has certain pre-requirements like creating a Auxiliary database, defining TNS connect string towards the target database (source) or a catalog database etc. You would definitely require connectivity towards the target database (source DB) or to a catalog db to perform a duplicate DB restore. You have an option to perform a duplicate db either from the backup or from the active database. Duplicate DB is supported to a database on the same host or a different host with a different db name. Duplicate DB is also used to create standby DB to configure a data guard setup.
Cross machine / out of place restore are supported to a database with the same name or different name on a different host. This restore do not need connection to the source database and catalog is option (may need catalog based on the restore scenario). Cross machine/out of place restores are not allowed on the same host. In case if the destination database name is different from the source, we utilize oracle NID utility to rename the database at the end after the entire database is restored and recovered. Corss machine / out of place restore could be utilized in a DR site scenario where the DR site is isolate from the production environment where you do not have network connectivity towards the source or the catalog db.
Duplicate db might be complicated as it has few pre-requirements before performing the restore and most restore run into issues if they are not met. As I mentioned earlier we rely on RMAN for duplicate db, after we trigger the duplicate command oracle takes over and performs the restore and recover and we will have less control to troubleshoot if we run into any issues during the restore and may need to restart the restore from beginning but we/dba’s will have more control and could troubleshoot and resume the restore or manually recover if needed.
Let me know in case of any other questions.
Regards,
Gowri Shankar
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