'Make sure volume type is thick.
:param lun_type:  Cinder volume type
:raises:
VolumeBackendAPIException: if volume type is not thick,
copying the lun is not possible.'

def _validate_lun_type_for_copy(self, lun_type):

    if (lun_type != CONCERTO_LUN_TYPE_THICK):
        msg = _('Lun    copy    currently    only    supported    for    thick    luns')
        LOG.error(msg)
        raise exception.ViolinBackendErr(message=msg)
