Now, you can register a target database with the recovery catalog. Log in to the target database server. Ensure that you can establish connectivity to the recovery catalog database.
For instance, one approach is to populate the TNS_ADMIN/tnsnames.ora file with an entry that points to the remote database. On the target database server, register the recovery catalog, as follows:
$ rman target / catalog rcat/Pa33word1@rcat
When you connect, you should see verification that you are connecting to both the target and the recovery catalog:
connected to target database: DB23C (DBID=3423216220) connected to recovery catalog database Next, run the REGISTER DATABASE command:
RMAN> register database;
Now, you can run backup operations and have the metadata about the backup tasks written to both the control file and the recovery catalog. Make sure you connect to the recovery catalog, along with the target database, each time you run RMAN commands:
$ rman target / catalog rcat/Pa33word1@rcat RMAN> backup database;
Backing Up the Recovery Catalog
Make certain you include a strategy for backing up and recovering the recovery catalog database. For the most protection, be sure the recovery catalog database is in archivelog mode, and use RMAN to back up the database.
You can also use a tool such as Data Pump to take a snapshot of the database. The downside to using Data Pump is that you can potentially lose some information in the recovery catalog that was created after the Data Pump export.
Keep in mind that if you experience a complete failure on your recovery catalog database server, you can still use RMAN to back up your target databases; you just cannot connect to the recovery catalog. Therefore, any scripts that instruct RMAN to connect to the target and the recovery catalog must be modified.
Also, if you completely lose a recovery catalog and do not have a backup, one option is to re-create it from scratch. As soon as you re-create it, you reregister the target databases with the recovery catalog. You lose any long-term historical recovery catalog metadata.
Synchronizing the Recovery Catalog
You may have an issue with the network that renders the recovery catalog inaccessible. In the meantime, you connect to your target database and perform backup operations. Sometime later, the network issues are resolved, and you can again connect to the recovery catalog.
In this situation, you need to resynchronize the recovery catalog with the target database so that the recovery catalog is aware of any backup operations that are not stored in it. Run the following command to ensure that the recovery catalog has the most recent backup information:
$ rman target / catalog rcat/Pa33word1@rcat RMAN> resync catalog;
Keep in mind that you have to resynchronize the catalog only if, for some reason, you are performing backup operations without connecting to the catalog. Under normal conditions, you do not have to run the RESYNC command.
