I would also like to see a VSS provider.

If you run the DSS as storage for a hyper-V cluster and want to take snapshots of the virtual machines running on the DSS your host machines must have the hardware VSS provider to enable backup jobs to run in parallel.

I don't want to snapshot the entire DSS, just the VMs that are stored on it.

It is possible to do this without the hardware VSS provider but it means taking the backups one at a time. We have 10 VMs stored on our DSS so this can take 14+ hrs and requires the SAN be put into redirected access mode.

With redirected access switched on one host access the storage and the other hosts access that host for access to the VHD files. This has a huge performance impact.

I feel that the DSSv6 can't be used in enterprise environments to host hyper-v failover clusters because of the lack of the VSS provider that prevents proper backups.