checks if the specified value is in the form of
    [server or cluster id][/database]

def is_server_or_cluster_db_address(value):
    """
    checks if the specified value is in the form of
    [server or cluster id][/database]
    """
    # check if value is an id string
    id_path = value.split("/")
    id = id_path[0]
    return len(id_path) <= 2 and (repository.lookup_server(id) or
                                  repository.lookup_cluster(id))