As root perform the following on each database server - one at a time:
1)Check to see if AUTOSTART is enabled:
# $GRID_HOME/bin/crsctl config crs
2) Disable the Grid Infrastructure for autostart on the database servers if the previous step indicated it is currently enabled for autostart.
# $GRID_HOME/bin/crsctl disable crs
3) Stop the Grid Infrastructure stack on the first database server locally:
# $GRID_HOME/bin/crsctl stop crs
4) Verify that the Grid Infrastructure stack has shutdown successfully on the database server.
The following command should show no output if the GI stack has shutdown:
# ps -ef | grep diskmon
5) Confirm that the clusterware resources are still up and running on the other nodes:
cd /opt/oracle.SupportTools/onecommand # dcli -g dbs_group -l root $GRID_HOME/bin/crsctl check crs
7) Before shutting down the DB node, check /etc/fstab for any nfs mounts that should be unmounted.
8) Shut the db node down so you can peform maintenance.