Thanks for ur suggestions everybody. i was very much worried about DBSNMP and multiple oraInventory . But dbsnmp doesn't seem to care about inventory and only reads /etc/oratab to discover the instances. so i decided to maintain one oratab and divide the inventory. Mark , i too had tough time with opatch before a couple of weeks . Thanks and Regards, Prem. -- //www.freelists.org/webpage/oracle-l