7.3.6 DB_UNIQUE_NAME Support for Multiple Clusters Sharing Exadata Storage

You can now use the same DB_UNIQUE_NAME value for databases that share the same storage. This feature enables Oracle Multitenant clustered databases sharing the same storage cells to have the same DB_UNIQUE_NAME.

In previous releases, multiple clusters could share Exadata storage if the DB_UNIQUE_NAME value for each instance was globally unique across all clusters. In Oracle Exadata System Software release 19.1.0, each cluster can have its own DB_UNIQUE_NAME namespace. This means matching DB_UNIQUE_NAME values are allowed between different clusters. For example, in prior releases, cluster1 and cluster2 could have only one database (either in cluster1 or cluster2) with the DB_UNIQUE_NAME parameter set to db1. In this release, if each cluster configures ASM-scoped security, then both clusters can have a database with the DB_UNIQUE_NAME parameter set to db1.

This feature eliminates the need for different clusters that share Exadata storage to coordinate the DB_UNIQUE_NAME assignments to avoid a name conflict. Each cluster is free to choose any DB_UNIQUE_NAME value, without having to coordinate with other clusters, as long as ASM-scoped security is configured for each cluster.

When ASM-scoped security is configured, the ASM cluster name is used to qualify the DB_UNIQUE_NAME for access to the storage servers. The metrics and stats collected for each database also use the asmcluster.database name qualification in various areas including I/O Resource Management (IORM), Flash Cache, quarantines, and cell offloading.

WARNING:

If you configure databases to have the same DB_UNIQUE_NAME, then those databases cannot be backed up to Oracle Zero Data Loss Recovery Appliance. The DB_UNIQUE_NAME for each database instance must be unique within the scope of the Oracle Zero Data Loss Recovery Appliance.

Minimum requirements:

• Oracle Exadata System Software release 19.1.0
• Each database with the same DB_UNIQUE_NAME must be in a different Oracle ASM cluster
• ASM-scoped security configured for each Oracle ASM cluster