[ceph-users] Out of Memory after Upgrading to Nautilus

I manage a historical cluster of severak ceph nodes with each 128 GB Ram and 36 OSD each 8 TB size. The cluster ist just for archive purpose and performance is not so important. The cluster was running fine for long time using ceph luminous. Last week I updated it to Debian 10 and Ceph Nautilus. Now I can see that the memory usage of each osd grows slowly to 4 GB each and once the system has no memory left it will oom-kill processes I have already configured osd_memory_target = 1073741824 . This helps for some hours but then memory usage will grow from 1 GB to 4 GB per OSD. Any ideas what I can do to further limit osd memory usage ? It would be good to keep the hardware running some more time without upgrading RAM on all OSD machines. Any Ideas ? Thanks Christoph