When I add in new nodes, install the MLNX_OFED drivers from Mellanox. Strangely I was only able to randomly ping to selected existing or new nodes on the Cluster. This was quite a curious problem.
When I do a ibstat, but when you do a ibping test (Installing Voltaire QDR Infiniband Drivers for CentOS 5.4), the test will failed for selected nodes in the cluster, but others will be able to ping back.
Yes, both openibd and opensmd services are started for all nodes on the cluster,
After some troubleshooting, the only way was to stop all the opensmd service for all the nodes (existing and new) and restart it again
# service openibd restart
# service opensmd restart