In 11gR2 RAC configuration, after planned shutdown I wanted to start the Grid infrastructure. So I issued crsctl start crs command, which resulted in following error
# crsctl start crs CRS-4013: This command is not supported in a single-node configuration. CRS-4000: Command Start failed, or completed with errors.
Being a development cluster, initially I thought someone have messed up with the RAC configuration by switching OFF the RAC. So to check the current configuration I issued following commands.
cd $GRID_HOME/rdbms/lib ar -t libknlopt.a | grep -c kcsm.o (return 0 if RAC is disabled or a number >0 if enabled)
This command returned value 1. Which means RAC was ON.
There was nothing obvious in the log, which points to the cause of this error. Also CRS was running on other node.
Tried with few more things
# crsctl start resource -all # /etc/init.d/ohasd start
But still could not start the CRS.
Finally deconfigured the CRS
# /oragrid/crs/install rootcrs.pl -deconfig -force
Then again configured it
Last approach worked, but I could not ascertain the root cause of this error.