This was posted to the github page and ceph mailing list. This bug affects all Debian/Ubuntu distros using the packages from repo. This does affect proxmox. With the patch people are seeing 3-5x increase in both write speed and latency. The Ceph team has said they will backport this patch all supported version.
github.com
cmake/modules/BuildRocksDB.cmake: inherit parent's CMAKE_CXX_FLAGS by tchaikov · Pull Request #54918 · ceph/ceph
CMake allows us to customize CMAKE_CXX_FLAGS by setting CXXFLAGS environmental variable. and Debian's debhelper also sets CXXFLAGS when it builds cmake projects for customizing the building flags. ...
github.com
