Oracle 12c multitenant

Oracle has catch up with time. With the 12c revolutionary database release, no longer a single instance is limited to a  server though many shops run multiple instances within a single server. However it prohibits the sharing of background processes. With 12c, one is able to sharing a server's resources eg: CPU, memory among different "instances".

Figure show the new 12c architecture design



 Source: Oracle docs


 In 12c, you create a CDB.
There's exactly one

• 1 CDB$ROOT (aka. the root). 
• One PDB$SEED.
• Zero or more PDBs (ie. user created PDB)

Familiarize with some new terms and concepts

Container: Can be a PDB, CDB

I downloaded the Oracle 12c database (12.1.0.1.0) from Oracle website for testing. There are two zip files for my Linux-x64 installation.  It's about 2.4GB in size.

Extract the zip files, and perform the normal straight forward installation --> ./runInstaller

The installation was pretty quick it finished within 30mins in my environment. I used the DBCA to create a database for testing.

To verify that CDB is enabled:
show parameter enable_pluggable_database = TRUE (This is the value it should return)

In my next post, I will write about connections to the PDB and some verification commands.