Linux client and cloning system drive

I am running a Urbackup server and thought about also cloning the servers systemdrive for backup purposes. It is a Linux machine (Debian/ OMV).
I have deployed a client on the machine via a docker and succsesfully attached it to the server component of Urbackup. Now I wonder if it is possible to perform a clone of the system drive on Linux.
The UrBackup web UI tells me “not supported” under the respective field.