As a result, a database must be in ARCHIVELOG mode to use an inconsistent
backup method.
Full and Incremental Backups
Full backups include all blocks of every datafile within a tablespace or a database; it is essentially
a bit-for-bit copy of one or more datafiles in the database. Either RMAN or an operating system
command can be used to perform a full backup, although backups performed outside of RMAN
must be cataloged with RMAN before they can be used in an RMAN recovery operation.
In Oracle 11g, incremental backups can be level 0 or level 1. A level 0 backup is a
full backup of all blocks in the database that can be used in conjunction with differential,
incremental, or cumulative incremental level 1 backups in a database recovery operation. A
distinct advantage to using an incremental backup in a recovery strategy is that archived and
online redo log files may not be necessary to restore a database or tablespace to a consistent
state; the incremental backups may have some or all of the blocks needed. An example of using
level 0 and level 1 incremental backups is presented later in this chapter. Incremental backups
can only be performed within RMAN.
Image Copies
Image copies are full backups created by operating system commands or RMAN backup as copy
commands. Although a full backup created with a Unix cp command can be later registered in
the RMAN catalog as a database backup, doing the same image copy backup in RMAN has the
advantage of checking for corrupt blocks as they are being read by RMAN and recording the
information about the bad blocks in the data dictionary.
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