'Return the size[GB] of the specified LDEV.'

def get_ldev_size_in_gigabyte(self, ldev, existing_ref):

    ldev_info = self.get_ldev_info(_CHECK_KEYS, '-ldev_id', ldev, do_raise=False)
    _check_ldev(ldev_info, ldev, existing_ref)
    return (ldev_info['vol_size'] / utils.GIGABYTE_PER_BLOCK_SIZE)
