[ceph-users] Objects not removed (completely) when removing a rbd image

Hello, My setup is Ceph pike working with OpenStack. When I deleted an image, I found that the space was not reclaimed. I checked with rbd ls and confirmed that this image was disappeared. But when I check the objects with rados ls, most objects named rbd_data.xxx are still existed in my cluster. rbd_object_map and rbd_header were already deleted. I waited for several hours and there is no further deletion happed. Is it a known issue, or something wrong with my configuration? br, Xu Yun