Do I have to run "hastart" on each node to manually startup the cluster?

Yes. If you need to manually startup the cluster, you have to run "hastart" on each node. There is no command to startup VCS on every node. If you only execute "hastart" on one node, VCS will come up, but it probably won't startup your Service Groups. VCS has to probe each machine the Service Group can online on, and it can't do that if VCS isn't running on one of the nodes.