Recovery Catalog Database (Recover Catalog) ___ Database

By default, the backup information is stored in the control file in the target database. The so-called use of control files will be very insecure, because once the backup files are lost, not only the database crashes, Rman backup information will also be lost (in terms of personal use, I do not feel so serious, 9i of control file backup is diverse, And there are many ways to restore and rebuild, so if you lose control files without using the recovery directory, do not think it is over, ready to touch the feet to leave. Google searches for Rman control file recovery, and you'll find countless pages that can save your job. Oracle 9i and later versions provide the ability to automatically backup the control files, and do not need to use the recovery directory to a large extent. Of course, if you want to manage more databases, then you can use the recovery directory or recommend the use of the recovery directory, the advantages of using the recovery directory are as follows (hint: especially relative to the control file, and then prompted: including but not limited to the following items): Storage Rman Scripts retain more historical backup information At the same time, management and backup of multiple target databases from the above, catalog mainly can keep more backup information and easy to manage multiple target database, if you need to back up the target database more, use catalog can help you save some operations. But if only a single database, whether to use catalog is open to question, after all, catalog itself also needs to be managed and maintained, all the backup examples in this book are in the Nocatalog mode of operation. Tip Even with catalog, the control files for the target database record the backup information, but are limited by the size of the control file and may save less records than the catalog. The number of record bars saved by the backup information in the control file is controlled by the initial parameter control_file_record_keep_time, which is in days, the default value is 7, the value is significantly smaller and is recommended to be set at least 14. Also, do not set this value to 0 unless you are certain that you are not ready to use Rman to back up the database. Similarly, if you choose to use the catalog method, do not forget to make a backup of the catalog database yo, of course, for this library, you do not have to use Rman to do backup, exp is a good way, simple and convenient, anyway, Rman catalog also take up much space. And after the exp backup, once the catalog database fails, it may be easy to recover through Imp.