Recently there was a discussion about upgrading to rhel6 on the rhelv6-beta list
http://www.mail-archive.com/rhelv6-beta-list-H+wXaHxf7aLQT0dZR+AlfA@public.g...
Where did I got that link ? Here is a hopefully working one: http://www.mail-archive.com/rhelv6-beta-list@redhat.com/msg00076.html
http://wiki.centos.org/HowTos/MigrationGuide?highlight=%28upgrade%29
Ok, I see, seems too risky versus the real gain.
I'll then do my test and playing around with gfs2 and all with the rhel6 beta, take note and re-install from scratch when CentOS 6 comes out, hopefully sooner than later.