DRBD on top of Ceph

Would it be possible to have DRBD directly running inside a Ceph Pool? I have a backup machine with files stored directly on disk. The offsite backup machine has Ceph installed and configured on all the disks. I would like to have a second replica of the backup data on the offsite backup machine, but I'm a bit confused at which 'layers' DRBD and Ceph operate. Would it be possible to create a RBD pool at the offsite backup machine and configure DRBD directly on that or, do I need to go the route where I run a virtual machine using Ceph and configure DRBD in the virtual machine as a abstraction layer? Edit: The reason the (single node) offsite backup machine is running Ceph is because it is mirroring the pools of a (multi node) main Ceph cluster. In addition to the main Ceph cluster we have a backup server creating file backups of the machines running on the cluster. This is a simple RAID5 configuration where the data is stored on. To have a extra copy of the backup data I also want to sync it, using DRBD so that I do not have a problem with small files, to the offsite backup machine. But as the disks of the backup machine are already configured to be a Ceph OSD I need to store it somehow on in a Ceph pool.