IN rac, while technically you have one database, you should have at least two instances of that database (one per server), and assuming you do not share your oracle home, you also have multiple oracle installations, etc. If your disks are properly mirrored onto separate storage devices, you also have redundancy at the datafile level (including the system tablespace). You just have to set it up correctly ...mirrors do a really good job of producing a copy...even of ugly stuff...I know since I look in the mirror when I shave. Mirrored system tablespaces are there to protect against single drive failures. You still only have 1 system tablspace-good, bad or ugly ===================================== 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.