In addition to bit-for-bit image copies of datafiles (the default in RMAN), RMAN can generate
full and incremental backups of datafiles, control files, archived redo log files, and SPFILEs that
are in a special format, called backupsets, only readable by RMAN. RMAN backupset backups
are generally smaller than the original datafiles because RMAN does not back up unused blocks.
Chapter 1: Getting Started with the Oracle Architecture 29
Oracle Managed Files
Oracle Managed Files (OMF), introduced in Oracle version 9i, makes the DBA??™s job easier by
automating the creation and removal of the datafiles that make up the logical structures in the
database.
Without OMF, a DBA might drop a tablespace and forget to remove the underlying operating
system files. This makes inefficient use of disk resources, and it unnecessarily increases backup
time for datafiles that are no longer needed by the database.
OMF is well suited for small databases with a low number of users and a part-time DBA,
where optimal configuration of a production database is not necessary.
Password Files
An Oracle password file is a file within the Oracle administrative or software directory structure
on disk used to authenticate Oracle system administrators for tasks such as creating a database
or starting up and shutting down the database. The privileges granted through this file are the
SYSDBA and SYSOPER privileges. Authenticating any other type of user is done within the
database itself; because the database may be shut down or not mounted, another form of
administrator authentication is necessary in these cases.
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