...where would you put the drives? I dunno why you'd run FreeNAS on a box that can, at most, take 2 hard drives.
i mentioned freenas just because of ecc ram, which is an official recommendation for it. but yeah, a 2 disk zfs is not the most optimal solution. but if you are ok with 5 tb of usable storage, you can fit 2x5 tb seagate 2.5" hdds with minimal tray modding as discussed before. or wait for cheap 8tb m.2 nvme ssds
but the point here was the apu, a 35w 4350ge with 10-15w idle power consumption and 8 threads would be awesome, compared to those 6-10w tdp apollo lake integrated boards everyone uses.
anyways, all of this was hypothetic as ecc ram is not supported in a300.
You guys just need to have some more imagination! The A300 motherboard doesn't need to stay in the DeskMini case in order to function. And with M.2 to PCIe adapters you could easily add an expansion card to it. Plus, the little guy runs just fine off of a regular 12v DC power supply connection so you could hook up as many drives as you could attach to the expansion card with ease. So with 1 NVMe drive, 2 SATA ports, and an expansion card running over an X4 M.2 slot, you could probably have 7 drives without too much issue. Of course there are much easier and better solutions out there, but it's totally doable. lol