Changing RAC to noarchivelog mode

Whilst trying to change an Oracle 11g2 database to noarchivelog mode I kept getting the error “ORA-01126: database must be mounted exclusive and not open for this operation”.

The word “exclusive” reminded me this was part of a cluster. Here’s the commands I ultimately used …

sql> select log-mode from gv$database; -- to check the modes of all the nodes.
c:> srvctl status database -d CLUSTER_NAME -- check nodes are running
c:> srvctl stop database -d CLUSTER_NAME -- stop all nodes of the database
c:> srvctl status database -d CLUSTER_NAME -- check nodes are stopped
sql> startup mount exclusive; -- mount database just on this node
sql> alter database noarchivelog; -- change the log-mode
sql> select log_mode from gv$database; - check it worked
sql> shutdown immediate; -- shutdown this node
c:> srvctl start database -d CLUSTER_NAME -- startup all nodes of the database
sql> select log_mode from gv$database; -- check modes of all nodes
c:> srvctl status database -d CLUSTER_NAME -- check nodes are running

Of-course I used the actual name of the cluster instead of “CLUSTER_NAME” above.