Container(CDB) & Plug-able(PDB) Database

Plug-able Database & Container Database:

Background Processes	Shared by root CDB and All PDBs
Control File	Single Control file for entire CDB
Redo Log	Single Redo Log for entire CDB
SYSTEM Tablespace	Separate SYSAUX tablespace for the root and for each PDB.
SYSAUX Tablespace	Separate SYSAUX tablespace for the root and for each PDB.
Temporary Tablespace	one default temporary tablespace for the entire CDB; but we can can create additional temporary tablespaces in individual PDBs
Undo Tablespace	One active undo tablespace is needed for a single-instance CDB, or one active undo tablespace is needed for each instance of an Oracle RAC CDB.
Default Tablespace	We can specify a separate default tablespace for the root and for each PDB
Physical Datafiles	There are separate datafiles for the root, the seed, and each PDB.
Database Character-set	A CDB uses a single character set. All of the PDBs in the CDB use this character set.
listener.ora, tnsnames.ora, and sqlnet.ora	Single copy of listener.ora, tnsnames.ora, and sqlnet.ora file for an entire CDB. All of the PDBs in the CDB use these files.