Hi Carel , Tony , Niall & Scott , First, Thanx all for your replies. Hi Carel : Thanx for that TRUNCATE reminder and about DATA GUARD in 8.1.7. I was really not aware of it, thought it was from 9i. Many thanx for the URL.Great help :) Tony : >>Its not really a don't do, but you >>have to be aware that if you add a >>new datafile to the production db, >>then you must also manually add it >>to the standby. Recovery stops until >>the new datafile is added. thanx for the corection ! Niall : >>I wonder if renaming the database and >>moving the archivelog destinations are >>good ways to break the standby as well. Changing the archive log dest never came to my mind. let me test that too. Thanx Niall. Scott : >>http://www.emc.com/products/networking/srdf.jsp Thanks a many Scott. You have let me know something really new today :) I have to test all these in a couple of days on oracle 8.1.7.4/Solaris 9. I will sure,post , if there is any quite interesting. Another Question: ----------------- How about OS patches/upgrades ? OS patches/upgrades will not be a big issue ... i feel ... not sure though !! How about RDBMS patches/upgrades ???? Just rebuild the standby from scratch ?! Or is there any other workaround for it ? Thanks & Regards, Prem. -- //www.freelists.org/webpage/oracle-l