I've recently created a guest fileserver cluster using VHD Sets. Everything is working fine except i can't do backup on the fileservers. Windows VSS tells me it cannot create snapshots of VMs with shared drives attached to it, even though one of the new key features of VHD Set compared to Shared VHDX is host level backup.
Correct me if I am wrong, the idea is to get data shared between guest cluster and also backup properly. If so, I would suggest to build a file server on top of iSCSI storage presented to guest cluster as CSV. For the case, storage would be shared between VMs as well as available for backup jobs using any kind of setup. HPE VSA, StarWind, UnityVSA are the software that do the job.