Thank you for the clarification Davey.
I'm used to do it via dbua which I find to be a very handy piece of software.
I'll try whitout using it as soon as I have some spare time.
Last but not least...
dbua step 1 of 7 reads "Select the database you want to upgrade. Make sure the selected database has been started". Please note dbua is pointing to Ora9i binaries.
waitecj was right too.
If would be confident to install Ora9i in one of RAC nodes, open database using new Ora9i binaries and, upgrade it to 10g
Thank you all
