Best practice for VM with 2TB of data

Hi,

I have a small business setup here, with only one server machine. Windows Server 2012 with Hyper-V role plus 2 important Windows VMs on it. One of them is a file server with ca. 2 TB of user data; about 40% of this data needs to be backed up daily (rest is archive data that is read-only for users and backed up rarely at certain points in time).

Backup target is a NAS box, and an RDX for off-site storage once a week.

My idea is to backup the VM from the hypervisor, i.e. agent-less (and de-select the archive drive in the regular backups). However, my impression is that selecting the drives in this big VM seems troublesome in ABR, at least in my installation (support is informed already).

So, I personally would rather prefer another option, lets call it PlanB:
PlanB would be to only backup the system drive of this VM, and backup all user data in an agent-based, separate backup job. This would give even smaller tib images, which are easier to handle in a disaster scenario, I believe.

Are there any experiences with such an environment? How would you do it?

(I am also weighing the options of using VHDX files or a pass-through disk for my 2 TB.
Considering the fact that in hyper-v it is not possible to exclude VHDXs from snapshots, I am tempted to go for pass-through, but I wonder whether there are any caveats with respect to backup. I understand I would definitely need PlanB in that scenario, right?)

Thanks for any suggestions / experiences,
Philipp