Pl clarify if you are performing a database install or grid install - there is a separate forum for grid install issues.
CentOS is not supported/certified OS version, so things may or may not work as expected. Support OS versions are listed in the Install Guide for your specific software at http;//docs.oracle.com
It is a grid install.
I'm using it for lab purposes
Moved to the Grid Install forum.
CentOS is not a supported OS, so expect issues.
Is there a reason you cannot use the freely available Oracle Linux ?
To be honest, I just received a VM ready for installing Oracle, beginners course, since is the most "similar" to RedHad distro, that's was the reason given to me.
I'm not an expert on linux either but I've found my way so far, planning on taking course soon, though.
But I considered doing that, I just downloaded Oracle Linux to study it, since it is supported officially.