I was installing Oracle 12c R2 with ASM but somehow the DBCA did not list ASM diskgroups. After struggling for hours, I could find a solution, not sure if it is approved by Oracle but it works !!
I’ve installed Grid infrastructure with user grid, and I was trying to install oracle database 12cr2 with oracle user but during this installation I wasn’t able to see any of my ASM disk in the select disk group.
log in as root user
/dev/oracleasm/ ls -lrt to check the permission on oracleasm directory chown -R grid:oinstall oracleasm cd /dev/oracleasm/disks
Login as grid user
cd $ORACLE_HOME cd bin ls -ld to check the permision on oracle directory chmod 6571 oracle ls -ld oracle
Login as oracle user
cd $ORACLE_HOME cd bin ls -ld oracle to check the permision
However, oracle directory permision in both grid user and oracle user must have the same permission. Therefore, issue the following command;
chmod 6571 oracle
Go back to select disk group and refresh.