The answer is 'it depends'
you will either have 'no impact', 'some impact' or a 'huge impact'
depends on your backup type, hardware, version, all sorts of things.
Have you any evidence to suggest that the backup is causing a problem?
there is also nothing run with full backups, unless on 10g they will take less time and therefore lessen any impact anyway
hello again, I don't have any real-world experience with RMAN but I'm contending w/ the DBA who says running backups through RMAN, **every day**, for 10 hours, does not impact our production performance. Never-you-mind that these backups are *full backups*