Non-CDB Architecture Deprecated in Oracle 12c R2 releases

Non-CDB Architecture Deprecated

Non-CDB is (Single instance database) which is currently used widely by everyone

From Oracle database 12c version 12.1.0.2, the non-CDB architecture is deprecated.

"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."

It is still supported and will not disappear immediately, but you should be considering the implications of this move now.

Let's get Started Now - It's time for the change

The multitenant architecture introduces a lot of changes for DBAs. If you upgrade to non-CDB in 12cR1, you may be "forced" to change to CDB in 12cR2, making your 12cR2 upgrade a bigger change than it needs to be. 

Maybe it's better to put the effort in upfront and switch now?

This is quite a subjective point and will depend on your time scales, training needs and the level of testing your applications require before making this change.

Prepare Yourself for the Future

The multitenant architecture is the future of the Oracle database.

 In the coming years, the DBAs who invest in learning the new architecture will stand out and those that don't will fall by the wayside.

Even if your decision is to go with the non-CDB approach in 12.1, you *must* start learning about the multitenant architecture now or you may end up making some really bad choices in the future. At a minimum, you need to start making sure your working practices minimize the impact that a move to multitenant architecture will make in future.