Whole
database backup: Includes all data files and at least one control
file (Remember that all control files in a database are identical.)
Partial
database backup: May include zero or more tablespaces and zero or
more data files; may or may not include a control file
Full
backup: Makes a copy of each data block that contains data and that is within
the files being backed up
Incremental
backup: Makes a copy of all data blocks that have changed since a previous
backup. The Oracle database supports two levels of incremental backup (0 and
1). A level 1 incremental backup can be one of two types: cumulative or differential.
A cumulative backup backs up all changes since the last level 0 backup. A
differential backup backs up all changes since the last incremental backup
(which could be either a level 0 or level 1 backup).
Offline
backups (also known as “cold” or consistent backup): Are taken while the
database is not open. They are consistent because, at the time of the backup,
the system change number (SCN) in data file headers matches the SCN in the
control files.
Online backups (also known as “hot” or inconsistent backup): Are
taken while the database is open. They are inconsistent because, with the
database open, there is no guarantee that the data files are synchronized with
the control files. To be used, inconsistent backups require recovery.
Image
copies: Are
duplicates of data or archived log files (similar to simply copying the files
by using operating system commands)
Backup
sets: Are
collections of one or more binary files that contain one or more data files,
control files, server parameter files, or archived log files. With backup sets,
empty data blocks are not stored, thereby causing backup sets to use less space
on the disk or tape. Backup sets can be compressed to further reduce the space
requirements of the backup.
Image
copies must be backed up to the disk. Backup sets can be sent to the disk or
directly to the tape.
The
advantage of creating a backup as an image copy is improved granularity of the
restore operation. With an image copy, only the file or files need to be
retrieved from the tape. With backup sets, the entire backup set must be
retrieved from the tape before you extract the file or files that are needed.
The
advantage of creating backups as backup sets is better space usage. In most
databases, 20% or more of the data blocks are empty blocks. Image copies back
up every data block, even if the data block is empty. Backup sets significantly
reduce the space required by the backup. In most systems, the advantages of
backup sets outweigh the advantages of image copies.
Read about RMAN, its setup and how to use
http://www.mybasicknowledge.com/2012/06/simple-steps-to-create-configure-rman.html
