This is not a "MUST" do thing. If we use one ORACLE_BASE for the GI and DB's as it will provide centralize diagnostic directory.
grid oracle base need to be separate from oracle oracle base
GI_HOME=/u01/app/grid/product/184.108.40.206 GI_BASE=/u01/app/grid ORACLE_HOME=/u01/app/oracle/product/220.127.116.11 ORACLE_BASE=/u01/app/oracle Central Inventory = /u01/app/oraInventory
absolutely no impact, we have been using the same ORACLE_BASE over the years and no problems at all.
Question 1: Other than role separation, what are the problems with having GRID and ORACLE user have the same ORACLE_BASE.
before GI installation the GI_HOME will be owned by "grid" user, but when you run the "root.sh" as part of installation then the script changes the necessary permission changes (some directories and files may owned by "root")
Question 2: Given that the HOMES for GRID and ORACLE share the same directory (/u01/app/18.104.22.168/...)
You mean ORACLE_HOME=/u01/app/22.214.171.124/oracle
Question 3: What is wrong with having the HOMES share the same directory path?