Benefits and Restrictions of RMAN in DataGuard

As we use RMAN to backup and restore the database in Simple scenarios. We can use it in Data Guard Environment same way.

Oracle Dataguard

Even we can use Physical Standby database backup to restore the Primary database and to recover the Primary database. But with some consideration as follow :

  • The recovery catalog is required when using RMAN in a Data Guard configuration for physical standby databases.
  • We can only use Physical Standby backup for the Primary database, But we can not use the Logical Standby Database for the Primary database.

According to Oracle MAA[Maximum Availability Architectute], best practices recommend that backup should be taken to Primary and Standby Database both side to

  1. Reduce Mean Time to Recover[MTTR].
  2. Handle outages at both sides
  3. Avoid introducing new site practices during switchover and failover

We have read offloading backup to Standby Database as the benefit of Data Guard many times.

Let us see how.

Database Backups and Archive logs backups taken at Physical standby Database are fully interchangeable at Primary Database. Means by just simply Restore Database command we can restore a backup taken by Physical Standby Database to Restore Primary Database.

Controlfile backups taken at Physical Standby Database is not interchangeable with a Primary database.

Recovery catalog should be used for Primary and Physical standby database and both databases must use the same recovery catalog.

It is not necessary to Register a Standby database. We can simply use a backup command to a backup database by connecting to a recovery catalog.

Restrictions and Usage Notes 

  1. Recover catalog must be used for Physical Standby database backup If we are taking Physical Standby database backup to use it for Primary database and we must resynchronize physical standby database immediately after backup. As there is no other way for the primary database to know about Physical standby database backup unless backups are stored in the recovery catalog.
  2. We can not take non-RMAN backup of standby controlfile or image-copy backup of controlfile.
  3. While taking backup from physical standby database backup we must connect the physical standby database with RMAN target key work and not the auxiliary keyword.

In next article, we will see Using the RMAN Recovery Catalog in a Data Guard Configuration.

Stay tuned for More articles on Oracle DataGuard

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About The Author

I am 11g OCP and OCE(RAC and GRID Infrastructure). Currently working as Oracle Database Administrator at _VOIS and Blogger (Freelancer) at Oracle-help . Previously I worked with Acute Informatics pvt ltd. and Mobile Tornado where I handled Banking Data Migration , created DR using log shipping , Golden Gate and Data Guard. I have experience of handling planned and unplanned DB role switchover and failovers and monitoring and troubleshooting Database Performance. Key skills : RMAN , GG , DG , RAC , Virtualization in OVMM.I have experience in Banking and Telecom domain. Reach me at : https://www.linkedin.com/in/jagruti-jasleniya

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