It basically performs a full scans of all your tables, so lots of "I" (a.k.a Input), and then writes either to disk (lots of "O", a.k.a Output) or to tape, depending on how you have it configured. So, if you're system is tight on I/O capacity, then yes - a backup of any type, not only RMAN, could certainly cause performance problems. And incremental backups, which are only available with Enterprise Edition, don't make as much difference as you might expect because they still require a full scan of all blocks - and then only the updated blocks since the last full or incremental of level-1 are written out to the backup device. That is, unless you're on 10g, where the change tracking file was introduced to avoid the full scan. Of course there is significant CPU involved with all that I/O as well, but usually the I/O is more of an issue since that's where most systems seem to be bottlenecked. Regards, Brandon ________________________________ From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of cosmin ioan so, can anyone tell me what kind of impact RMAN usually brings to a system, rather what toll it takes on one! :-) Privileged/Confidential Information may be contained in this message or attachments hereto. Please advise immediately if you or your employer do not consent to Internet email for messages of this kind. Opinions, conclusions and other information in this message that do not relate to the official business of this company shall be understood as neither given nor endorsed by it.