Big layer upload fails on Ceph/RADOS driver

...
class RadosGWStorage(_CloudStorage):
    def __init__(
        self,
        context,
        hostname,
        is_secure,
        storage_path,
        access_key,
        secret_key,
        bucket_name,
        port=None,
        maximum_chunk_size_mb=None,
    ):
        upload_params = {}
        connect_kwargs = {
            "endpoint_url": _build_endpoint_url(hostname, port=port, is_secure=is_secure),
        }

        super(RadosGWStorage, self).__init__(
            context,
            boto3.session.Session,
            connect_kwargs,
            upload_params,
            storage_path,
            bucket_name,
            access_key,
            secret_key,
        )

        chunk_size = (
            maximum_chunk_size_mb if maximum_chunk_size_mb is not None else 32
        )  # 32mb default, as used in Docker registry:2
        self.maximum_chunk_size = chunk_size * 1024 * 1024
...