Hi,
Oracle strongly recommends to take backup using rman i.e recovery manager a tool provided by oracle for taking backup and restorations thereby enabling a faster backups and more importantly faster recovery.
Also it is recommended to use catalog repository which stores critical backup information that is required for doing a database restore. It stores information about
 Â
a. Datafiles and archived redolog, backupset and backuppiece information
  b. Datafile copy information
  c. Archived redo logs and their copy information
  d. Tablespaces and datafiles on the target database information
  e. Stored scripts
Â
Also the repository should be create in a seperate database in a seperate machine so that we can retrive the repository information in case of failure .Also catalog repository database must be in archive log mode and must be backed up regularly s0 that repository failure can also be recovered
Generally for repository we create a sepearate database and include following tablespaces
 Â
SYSTEM TABLESPACEÂ :Â 100 MB (depends on the Oracle release)
  TEMP TABLESPACE      :  5 MB
  ROLLBACK SEGMENT   :  5 MB
  ONLINE REDO LOG      : 1 MB for each
  RECOVERY CATALOG   : 10 MB
Create a tablespace called “cattbs” for holding the recovery catalogSQL> Create tablespace cattbs datafile ‘path of datafile ‘ size 10M;create a user and his schema for using recovery catalog
SQL> Create user rman identified by rman
2 default tablespace cattbs
3 temporary tablespace TEMP
4 quota unlimited on cattbs;
grant connect ,resource and more importantly RECOVERY_CATALOG_OWNER role to rman user
SQL> grant connect,resource to rman;
SQL> grant RECOVERY_CATALOG_OWNER to rman;
Now create the RMAN catalog tables in the tablespace CATTBS .
  $ rman catalog rman/rman@RCAT1
 Â
    RMAN> create catalog tablespace cattbs;
This command is equivalent to running script catrman.sql present in $ORACLE_HOME/rdbms/admin folder .It basically create some tables in cattbs tablepspace like RC_DATABASE,RC_TABLESPACE,RC_DATAFILE,RC_STORED_SCRIPT,RC_STORED_SCRIPT
RC_STORED_SCRIPT_LINE which can be used to query important information about backups
Now you need to register the target database with the recovery catalog. Before this, if the database is running in MTS mode, make
sure that RMAN gets a dedicated server connection when connecting. For this create an entry in $ORACLE_HOME/network/admin/tnsnames.ora file
Register the target database .
  $ rman target sys/<password>@inst1_ded catalog
Â
    RMAN> register database;
The recovery catalog can be backed up using any appropiate backup scenario like, export command, cold or hot backup strategy.
   Export :
        Â
   $ exp rman/rman@rcat1 file = RCAT1_backup.dmp owner=rman
     Oracle recommends for Oracle9i :
   – Run the recovery catalog database in ARCHIVELOG mode so that you
     can do point-in-time recovery is needed.
   – Set the retention policy to a REDUNDANCY value greater than 1.
   – Back up the database onto two separate media (for example, disk and tape).
     You can specify BACKUP COPIES 2 when making backups.
   – Run BACKUP DATABASE PLUS ARCHIVELOG at regular intervals, to a media
     manager if available or just to disk.
   – Do not use another recovery catalog as the repository for the backups.
   – Configure the control file autobackup feature to ON.
     A recovery catalog can store information for multiple target databases
Thanks and Regards
Parikshit
