Mandatory attribute

You use the Mandatory persistent attribute to specify whether a managed resource is Mandatory or Non-Mandatory.

When a resource group is started, all managed resources within that group that are Mandatory must also be started. Managed resources that are Non-Mandatory (whose Mandatory attribute is set to False) might not be started when a conflict exists. If a managed resource that is Mandatory fails, the entire resource group is stopped and started on another node, but if a non-mandatory member of a resource group fails, the resource group stays Online on that node.

Resources that are members of a resource group are implicitly mandatory unless this attribute value is explicitly set to False. Member resources whose Mandatory managed resource attribute is False may be sacrificed in order to activate the resource group.

To set SelectFromPolicy to Ordered,Failback the resource has to be a mandatory member of a group.