Full backup is
complete backup of all the files (that includes every used data block in the
file) on the database. RMAN copies all blocks into the backup set or image
copy, skipping only data file blocks that have never been used. For a full
Image copy, the entire file contents are reproduced exactly. You can perform a full backup with or without RMAN. If you do not
use RMAN, then RMAN is called separately to catalog the backup. This means that
you can use this backup as a reference backup for an incremental backup with
RMAN. Most of the organizations only use them on a periodic basis
because they are time consuming. A Full
backup is different from a whole database
backup.
Whole backup
Backs up of the control file and all the database files
belongs to a database, but this backup is not cataloged, which means that you
cannot use it as a reference backup for an incremental backup with RMAN.
In a Full backup all datafile
blocks are backed up. As it was said already, a full backup applies to one or
more datafiles and up to all of them (database). The opposite of a full backup
is an incremental backup. An incremental backup level 0 backs up all datafile
blocks that have ever been used, and an incremental level 1 backs up anything
that has changed afterwards. One can do full backups with either RMAN or O/S
utilities.
A Full backup is
non-incremental RMAN backup. Note that "full" does not refer to how
much of the database is backed up, but to the fact that the backup is not incremental.
Consequently, you can make a full backup of one data file.
Level1 backup: A level 1 backup includes only those blocks that have been
changed since the "parent" backup was taken. Remember a parent backup
may be either a level 0 or a level 1 backup.
Level 0 backup: A level 0 incremental backup is physically identical
to a full backup and it includes every data block in the file except empty
blocks. The only difference is that the level 0 backup is recorded as an
incremental backup in the RMAN repository, so it can be used as the parent for
a level 1 backup.
Incremental backup: An incremental backup can be either level 0 or level 1.
1.
Differential
Incremental Backup: When using differential incremental backup (the default type of
incremental backup), RMAN looks for changed data blocks which were changed
after last level 1 incremental backup. If there's no level 1 backup made before
it, it takes a backup of the changed data blocks which were made after level 0
incremental backup. Differential backups are faster because
there are fewer changes stored, but they take longer at recovery time.
2.
Cumulative Incremental Backup: In a cumulative incremental backup RMAN takes
backup of all changed data blocks after level 0 or level 1 incremental
backup. Like a differential backup, incremental backups also back up only
the changed data blocks, but an incremental backup only backs up the data that
has changed since the last backup. If the last backup was also an
incremental backup, the current incremental backups only records "changes
to the changes", a much smaller set of block changes, and hence, a much
smaller recovery time than a differential backup.
