Performing Oracle User-Managed Backups - OCP: Oracle Database 12c Administrator Certified Professional - page 15

Parameter Files
In this section, we will address what parameter files and parameters are. We will then
discuss the two types of parameter files available in Oracle: the parameter file (pfile) and
server parameter file (spfile).
Parameter Files and Parameters
Every Oracle Database has a parameter file . Inside the parameter file you'll find a variety of
parameters that define global settings for that database. Parameter files are stored, by default,
in ORACLE_HOME/dbs or ORACLE_HOME/database , depending on the operating system in use.
Each parameter file will contain many different parameters. Parameters are used to
configure memory settings, auditing settings, destination directories for log files, and
archived redo log files. When configuring a database for backup and recovery, you will
configure several parameters, as you will see in the section “Configuring the Database
for Backup and Recovery.”
Parameters come in two flavors, static and dynamic. You must change static parameters
and restart the database in order for the parameters to take effect. Dynamic parameters can
be changed on the fly, without the need to restart the database.
You can find all the database parameters available in Oracle by looking
at the Oracle reference guide in the Oracle documentation available at
http://tahiti.oracle.com .
Parameter Files
The pfile is a text-based parameter file. To modify settings in this file, you simply open the
file with your editor and change it. Once your changes are complete, save the file. You will
then need to bounce the database to have those settings take effect.
Pfiles are kept, by default, in the $ORACLE_HOME/dbs (Unix) or %ORACLE_HOME%\database
(Windows) directory. The default name for a pfile is init<oracle_sid>.ora . So if your
Unix database is called ORCL , your pfile will be called initORCL.ora by default. Note that
case sensitivity applies here based on the operating system.
Server Parameter Files
The spfile is an Oracle database managed parameter file managed by the Oracle server.
We will first look closer at the spfile itself, and then we will discuss how to set parameters
when using an spfile.
What Is an Spfile?
An Oracle spfile differs from a text-based parameter file in that the Oracle server manages
it, and you as the DBA should never edit the file directly. The spfile is partly nontext (it has
a header and a footer), but the actual parameter settings are in plain text (so you can view
the file if you like and see what parameters are set to in the spfile).