Another area of feedback on the Hyper-V VSS Writer is that it does not give much by way of granularity beyond the level of the virtual machine. As a result of that, backup applications are stuck to backing up the entire VHD file, which could easily end up being a rather onerous process, expesially if the administrator is backing up to a separate DR site.

While the Hyper-V VSS writer provides backup admins significant flexibility in their ability to back up VMs in an application-consistent way while running backup applications in the physical machine, it does have a prominent limitation when it comes to VMs with pass-through storage. The VSS Writer excludes pass-through storage from the set of items to be backed up for a VM.