Oracle Database 12c Deployment Options

Introduction

Oracle Database 12c Multitenant Architecture is definitely the highlight feature of Oracle 12c. In this article we will review the Deployment Options for Oracle Database 12: Multitenant, Single Tenant, and Non-CDB.

Multitenant

Multitenant is the new paradigm in Oracle 12c which allows managing multiple Pluggable Databases in a single instance (i.e. Single Instance configuration) or multiple Pluggable Databases with multiple instances (i.e. RAC configuration). This is an extra cost option which is available only for Enterprise Edition Databases. In order to choose the Multitenant Option, check the "Create As Container Database" option in DBCA, as follows:

Single Tenant

Single Tenant is similar to the Multitenant in terms of the architecture and pluggable databases capabilities such as unplug/plug and PDB cloning options; however, it allows having only one single Pluggable database. This option does not require the extra cost license, as opposed to the Multitenant option. 

Non-CDB

Non-CDB basically means the old pre-12c architecture. In this option there is only one single Database with one single instance (i.e. Single Instance configuration), or one single Database with multiple instances (i.e. RAC configuration). In either case, Single Instance or RAC, there is only one single Database. The concept of Pluggable Databases is irrelevant and the 12c PDB options such as unplug/plug and clone are not available. In order to use the Non-CDB option, uncheck the "Create As Container Database" option in DBCA, as follows:

Single Tenant vs. Non-CDB

In case that you are interested in upgrading to Oracle Database 12c, but you are not interested in using the Multitenant option, you may ask yourself whether you should use Single Tenant or Non-CDB. Personally, I highly recommend on adopting  the Single Tenant due to the following reasons:

• Unplug/Plug - With Single Tenant you could unplug your PDB and plug it into a different CDB which could simplify upgrades and migrations in many cases.
• Fast Cloning - With Single Tenant you could fast clone your PDB to a different CDB which could simplify data migrations in many cases.
• Deprecation of Non-CDB Architecture - As per Oracle official documentation "The non-CDB architecture is deprecated in Oracle Database 12c, and may be desupported and unavailable in a release after Oracle Database 12c Release 2. Oracle recommends use of the CDB architecture.". This means that in the future we will all have to use either Single Tenant or Multitenant, so I believe it is better to get the knowledge and skills for managing Pluggable Databases as soon as possible.

Summary

I've created the following diagram which covers the 3 deployment options in Oracle Database 12c.

Additional Resources

• Deprecation of Non-CDB Architecture

• Oracle Multitenant (White Paper)

• Introduction to the Multitenant Architecture (Oracle Documentation)