Differences between nocatalog and catalog in RMAN

Differences between nocatalog and catalog in RMAN: The nocatalog method uses the control file as the catalog. Each backup must write a lot of backup information into the control file. More and more backup information will appear in the control file, that is, the backup information of RMAN is written in the local control file. Www.2cto.com catalog: you must first create a directory backup database (catalog, also known as the knowledge base) and create a recovery directory. That is, the backup information of the database is written into the recovery directory. When Oracle databases are backed up using rman nocatalog, Oracle uses controlfile to store RMAN backup information. Therefore, when using Rman nocatalog to back up a database, remember to back up controlfile. The initialization parameter control_file _ record_keep_time sets the backup information storage time, and the previous backup information is automatically cleared at the specified time: SQL> alter sysem set control_file_record_keep_time = 7 scope = spfile; note: when you use Rman nocatalog for restoration at www.2cto.com, the database must at least be in the "mount" State. That is, you must first load the control file. Otherwise, RMAN cannot find the recorded backup information. The precondition for Oracle startup mount is that control must exist. Therefore, you must restore controlfile Before restoring datafile. When using the Rman catalog method, you can start up nomount and restore controlfile. However, when using the Rman nocatalog method, you must restore the controlfile using the file method. Next, we will compare the restoration steps of Rman nocatalog and Rman catalog to establish a correct backup policy (the following recovery operations are performed online): Rman nocatalog recovery: 1) create an oracle runtime environment (including init or sp files) 2) restore controlfile to the specified location of the init file (or start NOMOUNT first, restore controlfile from autobackup in RMAN) 3) startup mount4) Rman, restore datafile, recover datafile5) alter database open resetlogs Rman catalog recovery: 1) Create an oracle runtime environment (including init or sp files) 2) Rman, restore controfile3) alter database mount4) Rman, Restore datafile, recover datafile5) alter database open resetlogs, we can see that during Rman nocatalog backup, controlfile must be backed up in file mode. In addition, because the controlfile is used to store backup information in nocatalog, we recommend that you increase the value of CONTROL_FILE_RECORD_KEEP_TIME in the Oracle parameter file (7 days by default). This parameter is set to $ ORACLE_HOME/dbs/initSID. ora (9i may also be in spfile and can only be changed using Oracle statements ). Directory recovery (catalog mode) supports the following command: {CREATE | UPGRADE | DROP} CATALOG {CREATE | DELETE | REPLACE | PRINT} SCRIPT. list incarnationregister databasereport schema at timereset databaseresync catalog www.2cto.com 1. The Resync command Resync can synchronize information between the database and the recovery directory. In actual cases, rman can automatically synchronize data. Synchronization is required under the following circumstances: Changes to the physical structure of the database · Increase or decrease of data files · tablespace deletion · Creation and deletion of rollback segments · every 10 archived logs are generated 2. Reset after the command resetlogs of the target database, you need to reset the recovery directory. The Reset command is used to Reset the recovery directory.