Database Reference
In-Depth Information
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/foo@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 can't 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 don't 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 aren't stored in it. Run the following command to ensure that the
recovery catalog has the most recent backup information:
$ rman target / catalog rcat/foo@rcat
RMAN> resync catalog;
Keep in mind that you have to resynchronize the catalog only if, for some reason, you're performing backup
operations without connecting to the catalog. Under normal conditions, you don't have to run the
RESYNC
command.
Recovery Catalog Versions
I recommend that you create a recovery catalog for each version of the target databases that you're backing up. Doing
so will save you some headaches with compatibility issues and upgrades. I've found it easier to use a recovery catalog
when the database version of the
rman
client is the same version used when creating the catalog.
Yes, having multiple versions of the recovery catalog can cause some confusion. However, if you're in an
environment in which you have several different versions of the Oracle database, then multiple recovery catalogs may
be more convenient.
