Oh, sorry about that confusion!
The Ceph is coming with Proxmox (
https://pve.proxmox.com/wiki/Main_Page )
and I use the same version for the NFS Ganesha host. The NFS Ganesha is from
download.nfs-ganesha.org.
root@nfsshares-a:~# cat /etc/apt/sources.list.d/*.list
deb
http://download.proxmox.com/debian/ceph-nautilus buster main
deb [arch=amd64]
https://download.nfs-ganesha.org/3/LATEST/Debian/buster/amd64/apt buster
main