That SQL statement will bring up instance orcl1 to non-cluster or exclusive mode. That requires the other instance to be down. If it's up, you would get "ORA-01102: cannot mount database in EXCLUSIVE mode". It's not possible to run one instance in non-cluster and the other in cluster (shared) mode. ________________________________ From: Saad Khan <saad4u@xxxxxxxxx> To: Yong Huang <yong321@xxxxxxxxx> Cc: "oracle-l@xxxxxxxxxxxxx" <oracle-l@xxxxxxxxxxxxx> Sent: Thursday, September 18, 2014 10:15 AM Subject: Re: Problem with cluster_database parameter ... But one more thing. When I refresh the database from prod on node 1, I issue following statement before shutting down the db: alter system set cluster_database=false scope=spfile sid='orcl1'; Can this sid= clause in the command be creating problem?