Returns a `list` of all the `ScaleIO_SDS` known to the cluster.  Updates every time - no caching.
        :return: a `list` of all the `ScaleIO_SDS` known to the cluster.
        :rtype: list

def sds(self):
        """
        Returns a `list` of all the `ScaleIO_SDS` known to the cluster.  Updates every time - no caching.
        :return: a `list` of all the `ScaleIO_SDS` known to the cluster.
        :rtype: list
        """
        self.connection._check_login()
        response = self.connection._do_get("{}/{}".format(self.connection._api_url,"types/Sds/instances")).json()
        all_sds = []
        for sds in response:
            all_sds.append(
                SIO_SDS.from_dict(sds)
            )
        return all_sds