As I moved most of my VMs to NAS, I should admit that whereas it is best solution in terms of providing adequate space for bulky VMs and snapshots and access convenience, you pay for it with decreased performance (at least if you compare it with running VMs off internal SATA 3 SSDs). Latter can be mitigated if you use NAS with good performance and configure it with array of disks, even if it won’t be on pair with SSD but it can be good enough (you also can leverage SSD drives for caching in certain NAS models, but this seems to be an extra possible point of failure in your setup). But what can not be mitigated with NAS it is high price tag for it, as not only you have to pay for NAS device and number of NAS optimized drives, you have to think about extra switch ports and UPS, both for NAS and your network equipment (provided that you use laptop as your VMs host you don’t need UPS for it at least :))
Maybe you can get away with clicking Retry button in response to I/O error you receive from your VM due to intermittent loss of network connectivity, but not always. For example today I was in process ob building K2 4.6.9 VM, going through update procedure of 4.6.7 and my switch went down for 30 seconds, but I was able to continue running my VM by clicking on Retry in response to I/O error message from my VM running from NAS. But the thing is that when I finished the process and decided to take a snapshot to save my work I got this:
Next, as at times Suspend/Resume procedure is able to “solve” minor issues (sort of), I tried this also, but VM just vent into hard restart. After that I won’t be able to power it on again with the following error:
Solution to this in cases when you are sure that your VM is not running is to delete any *.lck files in VM directory and try again.
So power loss on your switch and consequent connectivity loss even for 30 seconds or so may lead to quite harsh / unpleasant situation (think of situation when you continue to do your work to discover that your VM fails only when you decide to take a snapshot). So when you plan for running VMs from NAS budget for UPS to protect your setup for connectivity and/or data loss.