ControlSuite requires the Security Framework Service (SFS) on at least one server. Although there is no fixed maximum number of nodes that can be deployed, the recommendation is that no more than 3 SFS nodes be deployed per data center. Namely, each data centre should have 1, 2 or 3 SFS nodes. Having more than three SFS nodes is not explicitly forbidden, however having more adds complexity, and increases the possibility of problems. For example, if more nodes are deployed and three active nodes are lost in a data center, this will result in data loss, and those nodes will not work correctly. If more than 3 Security Framework nodes were deployed, they can either continue to be used or must be explicitly removed from the cluster before being taken out of service.