I'm trying to install a HA cluster + conga using 2 nodes with shared storage, the version of Oracle Linux I'm using is 5.7. I was able to install ricci and luci on both nodes and they start with no issues. I'm having an issue starting cman, the error message I get on both nodes is the following "FATAL: Module lock_dlm not found". The following line in subroutine "load_modules" in script "/etc/init.d/cman" seems to be the problem:
errmsg=$( /sbin/modprobe lock_dlm 2>&1 ) || return 1.
AFAIK, the lock_dlm module provides the inter-node locking protocol for the GFS and GFS2 shared file system.
Oracle provides OCFS2 (Oracle Cluster File System) as a shared disk file system and the drivers are included in the UEK kernel. Perhaps your solution will be to use OCFS2 instead of the GFS2 file system for your shared storage. Or use the supplied original RHEL kernel.