You have two options :
1. Automatic failover to DR
> For automatic failover to DR, you'd need to configure VCS with GCO, which would require you to install VCS on the third node (DR host) as well. The third node installation will be a single-node VCS install (unique cluster name and single node name). However, when configuring it under GCO, the other cluster (the primary cluster configuration) information will be needed.
2. Manual failover to DR
> For Manual failover, need to not to configure VCS on the DR host. Just install/configure VCS on both the nodes on the primary site. For DR failover, you can online the disks manually on the DR node, after offlining the service-group on the primary.
In either case, what you mention is absolutely correct. You'll need to replicate the data from primary to DR.
