Resource groups fail over from one node to another. When this failover occurs, the original secondary becomes the new primary. The failback settings specify the actions that occur when the original primary comes back online. The options are to have the original primary become the primary again (failback) or to allow the current primary to remain. You specify the option you want by using the Failback resource group property setting.
If the original node that hosts the resource group fails and reboots repeatedly, setting failback might result in reduced availability for the resource group.