Making Backups with RMAN - RMAN Recipes for Oracle Database 12c - page 180

Backing Up the Server Parameter File
Problem
You want to make a copy of the database's server parameter (spfile) file using RMAN so that you have a record of the
most recent database configuration.

Solution
Use the backup spfile command to back up the server parameter file, as shown here:

RMAN> backup spfile;

The previous command backs up the server parameter file currently in use by the database instance. Note that
you'll be able to backup the SPFILE only if you've started the instance with the SPFILE.

How It Works
To successfully back up a given server parameter file through RMAN, you must first make sure you start the database
with that server parameter file. You don't want to have used the text-based, init.ora style of parameter file. If you start
the database using an init.ora file instead of an spfile, RMAN won't back up the spfile, since it really isn't currently
in use by the instance.

■ RMAN can't make backups of the multiple server parameter files you may have on the server. it backs up only
the current server parameter file.

Note

Backing Up Data Files
Problem
You have a large database with thousands of data files, and you don't have the resources to take a daily backup of
your database. You therefore need to implement a strategy that can back up a subset of the database by copying a set
number of data files each day.

Solution
RMAN gives you the option of backing up individual data files. You can back up a data file either by using the data
file number or by using the data file name. The following example shows how to back up data files by specifying their
numbers. The format option specifies the format of each backup piece file name:

RMAN> backup datafile 1,2,3,4
format '/u01/app/oracle/rman/%d_%U.bus';