(sigh) Complex questions.
In a few words, urbackup has no image support for Linux clients because you don’t need it. At all.
Due to Linux unix-like nature which means “everything is a file” approach and variety and lots of filesystems and storage techniques (I meant such things like LVM/DRBD/Else) it is not easy provide simple enouth solution in your monolithic backup tool. But it is simple just to copy your files and set permitions on it. Everything you need is FILE! KISS principle in its best.
One more importaint thing:
Unix systems by and large avoid mandatory locks. There are a few cases where the kernel will lock a file against modifications by user programs, but not if it’s merely being written by another program. No unix system will lock a file because a program is writing to it.
(taken from StackExchange topic, thanks to Gilles)
So, it gives you an opportunity to backup almost everything, even database files with just cp command (if you don’t care about its consistency , but it’s another large theme, don’t punch me hard, I know about snapshots and “quiesce”)
What is general purpose of image backup? IMO, answer is “to provide disaster recovery solution” when “nothing works” and your hardware or system is damaged badly.
It’s not so hard to boot from media or network, simply re-create existed partition scheme, make filesystems on partitions/logical volumes, install and configure boot loader and simply recover all files from your file archieve. Fair enough? Yes.
And such open-source solution exists! Relax-and-Recover. It’s simple, written in bash.
Also, if you have several Linux workstations or servers you can centralize ReaR by DRLM.
So, I think there is no need to integrate something like Partclone or Fsarchiver with snapshot support into urbackup.
IMO, the best way is to integrate ReaR and UrBackup and get “better then image” backup solution for Linux in UrBackup. I had a conversation about such integration with @uroni . He told me that it is possible to implement it in version 1.5. I think I can help him if I’ll have much time for it.
And what do you think?