h1. Cluster Technology Comparison

Cluster Technology	{RedHat ClusterSuite}	{HP ServiceGuard}
From 2 node to 3 node	Requires clusterwide outage to change the 2-node parameter from 1 to 0	No outage required
From 4 node to 5 node	No outage required	Requires clusterwide outage to remove the lock disk configuration
Rolling Upgrade	From RHEL 4U2 to Higher version, it cannot be done in a normal rolling upgrade fashion. After the first node is upgraded, it won't join the cluster automatically because of the bug in Update 2. However, we can manually shutdown the services on node 2 and bring them up on node 1, then perform the upgrade on node 2. Once node 2 is upgraded and rebooted, it will automatically join the cluster.	Yes
Cluster Quorum disk/Lock disk	Requires RHEL 4U5. Requires clusterwide outage to introduce the quorum disk configuration. Might require to change/modify the fencing method	Requires clusterwide outage. Lock disk is not supported beyond 4 nodes.