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How to create a CDB and PDB in an ASM diskgroup. (Doc ID 1668402.1)

Last updated on MAY 10, 2021

Applies to:

Oracle Database Cloud Schema Service - Version N/A and later
Oracle Database Exadata Cloud Machine - Version N/A and later
Oracle Database Exadata Express Cloud Service - Version N/A and later
Oracle Cloud Infrastructure - Database Service - Version N/A and later
Oracle Database Cloud Exadata Service - Version N/A and later
Information in this document applies to any platform.


You can use Automatic Storage Management (ASM) to create CDBs and PDBs.

CDB is multitenant container database - a collection of schemas, objects, and related structures that appear logically to an application as a separate database. Within a CDB, each container has a unique ID and name.

The root and every pluggable database (PDB) is considered a container. PDBs isolate data and operations so that from the perspective of a user or application, each PDB appears as if it were a traditional non-CDB.

The root container, also called the root, is a collection of schemas, schema objects, and nonschema objects to which all PDBs belong. Every CDB has one and only one root container, which stores the system metadata required to manage PDBs. All PDBs belong to the root.
The name of the root is CDB$ROOT. The root does not store user data.

There are separate data files for the root, the seed, and each PDB.

There is one redo log for a single-instance CDB, or one redo log for each instance of an Oracle Real Application Clusters (Oracle RAC) CDB.
Also, for Oracle RAC, all data files and redo log files must be on shared storage.

The following prerequisites must be met before you can create and use a multitenant environment:
Install Oracle Database 12c.
The installation includes setting various environment variables unique to your operating system and establishing the directory structure for software and database files.
Set the database compatibility level to at least 12.0.0.


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