A method for exchanging a set of initial replicas comprising the steps of instantiating a set of additional replicas; transferring the current state of at least one initial replica to at least one additional replica in response to a triggering event; and phasing-in the set of additional replicas being in the transferred state, wherein the step of phasing-in comprises adding the set or a subset of additional replicas to the set or a subset of the initial replicas to form a combined set of replicas and/or substituting the initial set of replicas or a subset of the initial set of replicas by the set or a subset of additional replicas.
