<html> <head> <meta content="text/html; charset=ISO-8859-1" http-equiv="Content-Type"> </head> <body text="#000000" bgcolor="#CCCCCC"> <div class="moz-cite-prefix">On 28/03/14 19:31, Fabio M. Di Nitto wrote: </div> <blockquote cite="mid:5335CE1A.3060509@redhat.com" type="cite"> <pre wrap=""> Are there any known issues, guidelines, or recommendations for having a single RHCS cluster with different OS releases on the nodes? </pre> <pre wrap=""> Only one answer.. don't do it. It's not supported and it's only asking for troubles. </pre> </blockquote> Seconded. There are _substantial_ differences between Centos/RHEL 5 and 6 clustering. You can run one or the other OS, but you can't mix them. The on-disk format isn't affected. Best path is to setup a cluster in 6, shut down the 5 cluster, attach disks to the 6 cluster and bring it all back up. The 5 boxes can be converted to version 6 afterwards. (I'm going through this at the moment, as I have 2 EL5 clusters and 1 EL6 cluster.) TAKE NOTE: RHEL/CentOS6 clustering is not quite ready for prime-time - if you enable GFS2 quotas and someone busts his quota the machine will panic. </body> </html>