'Retrieve stats info from volume group.'

def _update_volume_stats(self):

    LOG.debug('Updating    volume    stats.')
    data = {'vendor_name': 'IBM', 'driver_version': self.VERSION, 'storage_protocol': self._protocol, 'total_capacity_gb': 0, 'free_capacity_gb': 0, 'reserved_percentage': self.configuration.reserved_percentage, 'QoS_support': False, 'multiattach': self.configuration.flashsystem_multihostmap_enabled}
    pool = FLASHSYSTEM_VOLPOOL_NAME
    backend_name = self.configuration.safe_get('volume_backend_name')
    if (not backend_name):
        backend_name = ('%s_%s' % (self._system_name, pool))
    data['volume_backend_name'] = backend_name
    ssh_cmd = ['svcinfo', 'lsmdiskgrp', '-bytes', '-delim', '!', pool]
    attributes = self._execute_command_and_parse_attributes(ssh_cmd)
    if (not attributes):
        msg = _('_update_volume_stats:    Could    not    get    storage    pool    data.')
        LOG.error(msg)
        raise exception.VolumeBackendAPIException(data=msg)
    data['total_capacity_gb'] = (float(attributes['capacity']) / units.Gi)
    data['free_capacity_gb'] = (float(attributes['free_capacity']) / units.Gi)
    data['easytier_support'] = False
    data['location_info'] = ('FlashSystemDriver:%(sys_id)s:%(pool)s' % {'sys_id': self._system_id, 'pool': pool})
    self._stats = data
