The software described in this documentation is either in Extended Support or Sustaining Support. See https://www.oracle.com/us/support/library/enterprise-linux-support-policies-069172.pdf for more information.
Oracle recommends that you upgrade the software described by this documentation as soon as possible.
Oracle RAC uses its own cluster stack, Cluster Synchronization Services (CSS). You can use O2CB in conjunction with CSS, but you should note that each stack is configured independently for timeouts, nodes, and other cluster settings. You can use OCFS2 to host the voting disk files and the Oracle cluster registry (OCR), but not the grid infrastructure user's home, which must exist on a local file system on each node.
As both CSS and O2CB use the lowest node number as a tie breaker
in quorum calculations, you should ensure that the node numbers
are the same in both clusters. If necessary, edit the O2CB
configuration file /etc/ocfs2/cluster.conf to
make the node numbering consistent, and update this file on all
nodes. The change takes effect when the cluster is restarted.