This section outlines the configuration steps necessary to get GFS running on top of DRBD in RHEL 4 clusters. These also apply to RHEL 4 derivatives such as CentOS 4.

RHEL 4 clusters keep their configuration in a single configuration file, /etc/cluster/cluster.conf. You may manage your cluster configuration either by editing this configuration file, or by using the system-config-cluster GTK2 GUI application. Preparing your cluster configuration is fairly straightforward; all a GFS cluster requires are the two participating nodes (referred to as Cluster Members in Red Hat's documentation) and a fencing device.

	Note
	For more information about configuring Red Hat clusters, see Red Hat's documentation on the Red Hat Cluster Suite and GFS.

After you have created your new DRBD resource and completed your initial cluster configuration, you must enable and start the following system services on both nodes of your GFS cluster: