db restarts

I want to shutdown 1 of 4 instances in my 10g rac. So I sqlplus from the blade and do shutdown. Dbconsole shows the instance as down. I can't login as a regular user from sqlplus. All good, except after 45 minutes I get an error saying operation aborted by user and the instance is back up.

I had already commented out all the lines in /etc/oratab and renamed dbora.

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