With RMAN one can perform various types of backup as shown
below.
·
Open or closed – Open backup is the backup taken when the
database is open: a backup of online, read/write data files. Closed backup is
the backup of any part of the target database when it is mounted but not open.
·
Full or incremental – A backup of type full is the back up of a
data file that contains every allocated block in the file being backed up. And
an incremental backup is either a level 0 backup or a level 1 backup.
·
Consistent or inconsistent – A consistent backup is the backup
taken when the database is mounted but is not open after a normal shutdown.
Whereas an inconsistent backup is the backup taken of any part of target
database when the database is open or when a crash occurred, etc.
Backup database using RMAN
In non-archive mode, using dos prompt type:
the RMAN prompt gets displayed.
Listing 1
RMAN>Connect Target
Connect to target database:Xxx<Dbid:123456789>
This is using the database of target file rather than the
recovery catalog.
A Dbid stands for Database Identifier which is a unique
identifier and found in all datafile headers and control files. It is used to
identify a file belongs to which database.
A simple example of taking backup in non-archived mode:
Listing 2
shutdown immediate; //shuts down the database
startup mount;
backup database; //starts backing up the database
alter database open;
In archivelog mode, the same command can also be fired to
backup the whole database.
Listing 3
backup database plus archivelog;
The backup command can backup the following type of files:
·
Database (which includes all datafiles as well as the current
control file and current server parameter file)
·
Tablespaces, except for locally-managed temporary tablespaces
·
Current server parameter file
·
Current control file
·
Backup sets
·
Current datafiles
·
Archived redo logs
RMAN does not back up the following:
·
Online redo logs
·
Transported tablespaces before they have been made read/write
·
Client-side initialization parameter files, etc
Restore database using RMAN
Restoring and recovering a database using RMAN uses even more
simple commands than backup.
Listing 4
restore database;
recover database;
RMAN has the intelligence to find out which datafiles are to
be recovered or restored and the location of backed up files.
