This really isn't an answer, but it is a suggestion:
According to Red Hat, RHEL 5 is in "Production Phase 3" where only "Critical Impact Security" and "Critical Impact Bug" fixes are being pushed and it goes out of general support on March 31, 2017. That's 15 months. I've worked places where that was an entire procurement cycle.
I realize (having worked in these sorts of environments) that it is not always possible to do a reinstall, but if your time and data are valuable I would REALLY suggest spending the time to get up to speed with RHEL 7, get a second machine up and running and configured right, then migrate your data over. This will let you re-plan your disk subsystems and get everything arranged right.
I would have put this as a comment, but it was too long. Sorry.