I bought a U-Nas case a while ago. Just a small NAS-style PC case with eight 3.5" disk bays. I built it up and played around with it, but never put it into service in my homelab. It just sat there (off) with Truenas or something on it for testing. Well, it was a good thing I never did anything with it as I needed it the day my Synology died last year. It was a DS1518+ on (a lot of) borrowed time having lasted nine years. I mentally toyed with buying a new NAS, but the idea of spending a few thousand dollars didn’t excite me (or the wife).
So, I loaded up Xpenology on a thumb drive and plugged it into my U-Nas. It did not take me long to see how easy this was to load up a Synology DSM and hit the ground running. Then, once I loaded all my disks in, it saw everything and asked if I wanted to upgrade the OS. Sure, why not?
So, all data intact and running a mostly generic set of hardware as a Synology only a couple of days later. Zero extra cost for me as I already had everything. But you can do this too with hardware you might have laying about. I highly recommend it.
That looks like the one I am using. I bought a tiny motherboard that had the newer Supermicro Optilink connections. This allowed for all eight bays to be used with smaller cables that helped airflow and it had one onboard M.2 slot that I am using as cache. I did also put the PCI-E ribbon cable in to use with a 10Gb card, but I should pull that out as it’s only using the 1Gb link where it sits.
I don’t recall where, but there was a whole buildout of this Unas case on some blog linked from reddit years ago and I just followed that except for changing the motherboard. The parts I swapped in did better on the build than the blog version. They had to trim things to make it all fit. I didn’t have to do anything like that. It just worked.
All in all, a very nice NAS package that has the same footprint as the Synology.