Complete High Availability System [duplicate]

If you do have just one Synology box shared between your Hyper-V machines, it can still be considered as a SPoF. It dies, you lose all the LUNs sitting there. For true HA you would need a second NAS box and some replication mechanism. Well, one thing that comes to mind is HA cluster with two Synology NAS devices. But AFAIK it doesnt rate well in the world of HA. Especially because of performance and slowness of failover. So mostly we usually lean toward some of SDS solutions like HPE VSA (http://www8.hp.com/us/en/products/data-storage/free-vsa.html), Unity VSA (http://www.emc.com/products-solutions/trial-software-download/unity-vsa.htm) and StarWind vSAN (https://www.starwindsoftware.com/starwind-virtual-san-free). I personally was playing around StarWind a lot and got all the things done very quickly. Their free version should be able to mirror your NAS boxes converting all the stuff into a full fledged virtual san. And finally I wouldnt use Synology for production tasks. It can flawlessly handling a backup jobs, but I doubt it is completely suitable for virtualized environments. So if I were you, I would leave Synology as a backup repository, load Hyper-V hosts with the local disks and create a storage pool wit help of one of the SDS mentioned above.