Deinstall 12.2.0.1 Grid Infrastructure Home After Being Upgraded to 18c GI

Grid Infrastructure 12.2.0.2 has been upgraded to 18c GI successfully. So 12.2.0.1 GI_HOME needs to be de-installed.  There are two ways to uninstall the old GI_HOME ( 12.2.0.1)

1) Detach GI_HOME and Remove the GI_HOME manually:

$ export ORACLE_HOME=/u01/app/grid/12.2.0.1
$ $ORACLE_HOME/OPatch/opatch lsinventory -all
$ cd $ORACLE_HOME/oui/bin
$ ./runInstaller -silent -detachHome ORACLE_HOME="/u01/app/grid/12.2.0.1"
$ unset ORACLE_HOME

-- as root user

# cd /u01/app/grid
# rm -fr 12.2.0.1

For any reason, if the above command fails, then on every node:

$ export ORACLE_HOME=/u01/app/grid/12.2.0.1 
$ $ORACLE_HOME/OPatch/opatch lsinventory -all 
$ cd $ORACLE_HOME/oui/bin 
$ ./runInstaller -silent -local -detachHome ORACLE_HOME="/u01/app/grid/12.2.0.1"
$ unset ORACLE_HOME
-- as root user
# cd /u01/app/grid
# rm -fr 12.2.0.1

2) Deinstall old GI_HOME by using “deinstall” tool :

a) Log in as root, change the permission and ownership of the old GI_HOME ( 12.2.0.1) on both nodes.

# chmod -R 755 /u01/app/12.2.0.1/grid
# chown -R grid /u01/app/12.2.0.1/grid
# chown grid /u01/app/12.2.0.1

b) Run “deinstall” under the to be deleted GI_HOME( /u01/app/12.2.0.1/grid).

$ /u01/app/12.2.0.1/grid/deinstall/deinstall

Checking for required files and bootstrapping ...
Please wait ...
Location of logs /u01/app/oraInventory/logs/

############ ORACLE DECONFIG TOOL START ############


######################### DECONFIG CHECK OPERATION START ################
## [START] Install check configuration ##
...
..
.

c) Refer and check the logs :

The Log of Deinstall 12.2.0.1 GI_HOME