Q. Can I use Storage Spaces inside a VM?

A. While Storage Spaces works inside a VM it is technically not supported per https://social.technet.microsoft.com/wiki/contents/articles/11382.storage-spaces-frequently-asked-questions-faq.aspx#What_types_of_drives_can_I_use_with_Storage_Spaces which states storage layers that abstract the disk are not compatible which includes VHDs. There is an exception for Azure based VMs which is documented at https://technet.microsoft.com/en-us/library/hh831739(v=ws.11).aspx#BKMK_AZURE. If you are just using on Hyper-V to test then you should be fine but do not use in production due to the lack of support.