I have been playing around with Storage Spaces and Hyperv Both Passing through a volume and just putting all my VM's on a giant ReFS partition It performs really well but I am having trouble getting it to not require manual intervention on each reboot. (If I create a ReFS using the whole pool size then I have to manually online the pool after each reboot). If I passthrough volumes then I have to manually mess around offlining the disk each time. It is really badly documented and I am not really yet experienced enough with powershell to know properly where to look. It is more than likely a properly of the volume. It is running on hyperv server 2012 booting from usb (The Kingston Recommended one for Windows 2 Go / 32 GB RAM / Xeon E3 1230v2). For what I need it is almost perfect. (I would perhaps prefer to passthrough physical nic's but the performance is good enough). I could go to ESXi and then passthrough the controller with both the disks on it to a VM but then I would need a hardware raid controller (And I don't really know that I am up for buying two and suitable disks). I have read all the docs relating to Storage Spaces / File Server Role / Hyperv Server on Technet and they are very very simple. (I have also tried to read the generic storage subsystem WMI docs but it is really complicated and I don't even know whether it properly relates to what I want to do).