You should back up your archive redo logs in your Oracle Databace on a regular basis. The archivelog files shouldn’t be removed from disk until you’ve backed them up at least once. I usually like to keep on disk any archive redo logs that have been generated since the last good RMAN backup.
Generally, I instruct RMAN to back up the archive redo logs while the data files are being backed up. This is a sufficient strategy in most situations. Here is the command to back up the archive redo logs along with the data files:
RMAN> backup database plus archivelog;
Sometimes, if your database generates a great deal of redo, you may need to back up your archive redo logs at a frequency different from that of the data files. DBAs may back up the archive redo logs two or three times a day; after the logs are backed up, the DBAs delete them to make room for more current archivelog files.
In most situations, you don’t need any archive redo logs that were generated before your last good backup. For example, if a data file has experienced media failure, you need to restore the data file from a backup and then apply any archive redo logs that were generated during and after the backup of the data file.
On some occasions, you may need archive redo logs that were generated before the last backup. For instance, you may experience a media failure, attempt to restore your database from the last good backup, find corruption in that backup, and therefore need to restore from an older backup. At that point, you need a copy of all archive redo logs that have been generated since that older backup was made.