An Oracle Data Guard configuration contains a production (primary) and standby database so that you can have high availability in the case of a disaster. The standby database becomes the primary database when the primary database has a planned or unplanned outage.
In the Commvault environment, you can use Unified Data Guard for either a single-instance Oracle database or an Oracle RAC database. The Commvault support is considered "unified" because it intelligently supports Oracle Data Guard for both single-instance Oracle databases and Oracle RAC databases. Therefore, you can use the procedures in this section for both types of Oracle databases.
When you configure the Commvault software for Oracle Data Guard, the software discovers the database role (primary or standby) and then picks the appropriate client storage policy or the appropriate instance storage policy for the data and the log backups. You can configure the software to run the database and the log backups on different instances that also have different roles.
You configure an Oracle Data Guard pseudoclient that contains all the primary and standby nodes. The nodes can be on the same or different data centers. By default, the software uses the pseudoclient storage policies.
You can configure storage policies for the physical clients that host the primary and standby servers. When the primary and standby servers are at different data centers and a failover occurs, the software cannot use the storage policies that you configured for the pseudoclient, because it needs access to a local MediaAgent. After a failover, the software uses the physical client storage policies and automatically reconfigures them to use the location aware MediaAgent.
Using Commvault software, you can make backups of the standby database even if the primary database has read-only tablespaces and you want to make backups of the standby database using the "Skip Read Only" option. RMAN does not natively support skipping read-only tablespaces when running backups on standby databases; if it is attempted the job fails and the following error is output:
RMAN-06131: SKIP OFFLINE and SKIP READONLY are only allowed with current control file
Commvault software intelligently omits any read-only tablespaces when making the backup, which allows the backup to complete successfully.
Note
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You must use the RMAN recovery catalog so that the primary database knows about the backups that you performed on the standby databases.
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Disk caching of archive log backups is not supported with Unified Data Guard configurations.
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All the clients in the Data Guard environment should be at the same Commvault release level for the best operation of the Data Guard configuration.
Configuration
Collect the list of all the primary instances and the standby instances that are part of the configuration, along with the user credentials for each instance.
An archivelog subclient needs to be created on each database site. Create an archivelog subclient that contains all the primary nodes, and similarly configure another archivelog subclient that contains all the standby nodes. If there are multiple standby sites, each site needs to have an archivelog subclient which backs up logs from that site and that has the archivelog delete option enabled.
The archivelog subclient for the primary site should have streams configured for only the primary nodes and the streams for the remaining nodes should be set to 0. For the standby site, configure streams for the standby nodes only and set the remaining node streams to 0 in that standby archivelog subclient. It is a best practice to use the same schedule for all the archivelog subclients and use the archivelog delete option.
Backup Operations Run Locally and Use Local Storage
In this scenario, the backup operations are run locally.
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Create a pseudoclient for Oracle Data Guard using the procedure for an Oracle RAC client.
Note
You must add all of the primary and standby databases to the pseudoclient.
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Configure a storage policy for the client. For information, see Configuring a Client Storage Policy for Oracle Data Guard.
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Create a subclient for the primary database and the standby database. For more information, see Configuring an Oracle Data Guard Subclient.
Backup Operations Run on the Primary or Standby Server
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Specify the servers that run backups in an Oracle Data Guard configuration.
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Create a pseudoclient for Oracle Data Guard using the procedure for an Oracle RAC client.
Note
You must add all of the primary and standby databases to the pseudoclient.
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If your primary and standby databases are in different data centers, you must configure a storage policy for all clients that host the primary and standby databases. For information, see Configuring a Client Storage Policy for Unified Oracle Data Guard.
Backups
Perform backups on the primary database. You can use a combination of full and incremental backups depending on your RPO.
For more information about Oracle single-node backup operations, see Oracle Backups. For more information about Oracle RAC backup operations, see Oracle RAC Backups.
Restores
You can restore the backups to the primary database or the standby database.
For more information about Oracle single-node restore operations, see Oracle Restores. For more information about Oracle RAC restore operations, see Oracle RAC Database Restores.