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CONTROLFILE AUTO BACKUP

July 11, 2010 3 comments

RMAN is one of the very useful utility provided by Oracle for backup and recovery Purpose. Oracle online backups were introduced with Version 6, where tablespace must be kept in backup mode in order to take online backups.

RMAN has following default parameters and its default values:

RMAN> show all;
RMAN configuration parameters are:
CONFIGURE RETENTION POLICY TO REDUNDANCY 1; # default
CONFIGURE BACKUP OPTIMIZATION OFF; # default
CONFIGURE DEFAULT DEVICE TYPE TO DISK; # default
CONFIGURE CONTROLFILE AUTOBACKUP OFF; # default
CONFIGURE CONTROLFILE AUTOBACKUP FORMAT FOR DEVICE TYPE DISK TO '%F'; # default
CONFIGURE DEVICE TYPE DISK PARALLELISM 1 BACKUP TYPE TO BACKUPSET; # default
CONFIGURE DATAFILE BACKUP COPIES FOR DEVICE TYPE DISK TO 1; # default
CONFIGURE ARCHIVELOG BACKUP COPIES FOR DEVICE TYPE DISK TO 1; # default
CONFIGURE MAXSETSIZE TO UNLIMITED; # default
CONFIGURE ENCRYPTION FOR DATABASE OFF; # default
CONFIGURE ENCRYPTION ALGORITHM 'AES128'; # default
CONFIGURE ARCHIVELOG DELETION POLICY TO NONE; # default
CONFIGURE SNAPSHOT CONTROLFILE NAME TO 'F:\ORACLE\PRODUCT\10.2.0\DB_1\DATABASE\S
NCFORCL.ORA'; # default

Or

RMAN>  SHOW CONTROLFILE AUTOBACKUP;

RMAN configuration parameters are:
CONFIGURE CONTROLFILE AUTOBACKUP OFF;

By default CONTROLFILE AUTOBACKUP is OFF. But it is strongly recommended enabling CONTROLFILE AUTOBACKUP ON.

Advantage:

  • RMAN can recover the database even if the current control file, recovery catalog, and server parameter file are inaccessible.
  • Restore the RMAN repository contained in the control file when the control file is lost and you have no recovery catalog. You do not need a recovery catalog or target database control file to restore the control file auto backup.
  • Control file auto backup can keep track of add a data file, resize, increase/decrease the size of data files or etc.
  • If CONFIGURE CONTROLFILE AUTOBACKUP is ON, then RMAN automatically backs up the control file and the current server parameter file (if used to start up the database) in one of two circumstances: when a successful backup must be recorded in the RMAN repository, and when a structural change to the database affects the contents of the control file which therefore must be backed up

To perform control file auto backup on issue the following command

RMAN> CONFIGURE CONTROLFILE AUTOBACKUP ON;
new RMAN configuration parameters:
CONFIGURE CONTROLFILE AUTOBACKUP ON;
new RMAN configuration parameters are successfully stored
starting full resync of recovery catalog
full resync complete
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