'Periodically runs to update ssc information from the backend.
The self._ssc_stats attribute is updated with the following format.
{<volume_group_ref> : {<ssc_key>: <ssc_value>}}'

@cinder_utils.synchronized('netapp_update_ssc_info', external=False)
def _update_ssc_info(self):

    LOG.info("Updating    storage    service    catalog    information    for    backend    '%s'", self._backend_name)
    relevant_pools = self._get_storage_pools()
    if self._client.features.SSC_API_V2:
        self._update_ssc_info_v2(relevant_pools)
    else:
        self._update_ssc_info_v1(relevant_pools)
