u/Stu_ffing

I'm currently running TrueNas on an ODROID H4+ (Intel N97), 16GB DDR5, using all 4 SATA slots in RAID-Z1, for a total of ~32TB HDD storage and single failure tolerance. It's working great so far - more than enough for my storage needs, and since I don't run any intense workloads on it the hardware is more than enough for me.

My biggest issue is that it's LOUD; I want to leave it running 24/7, but that's just not an option with its current noise level. The noise is coming 100% from the drives - definitely my fault for buying server drives and using ODROID's ultra-barebones case; the drives are hard-mounted with no noise isolation whatsoever. There is no place in my current apartment that I can place this thing where I won't hear it. The idea was to buy a 'real' case eventually, and here we are.

I'd like to make some improvements to it to make it more functional as a 24/7 home server, rather than just a cold storage box that I turn on every once in a while to run backups. I had the following as an idea, and I'd love some feedback on whether this is possible, a good idea, or if there are better options.

1. Attach ODROID's M.2 4x1 or 2x2 card expansion
2. Install 2 or 4 budget (lol) M.2s as a separate, always-available JBOD pool
3. Migrate the hardware into a new mITX enclosure, possibly using ODROID's mITX kit
4. Configure the HDD pool with an aggressive spin-down policy
5. Mirror the M.2 storage pool onto the HDD pool when data is written to them (maybe with a size/data-written threshold?)
6. Run my regular backup jobs directly to the HDD pool

The idea is to maximize what I've already got in order to suite my current needs rather than going all-out on a new build with new MOBO, CPU, PSU, etc. Spinning up the HDDs 1/week or less is sufficient for my backup needs; and perhaps I could also run SMART tests when that happens. I understand that frequent spin-up/downs are not ideal, but right now the alternative is the exact same just not automated 🤷 I'd also like to keep this thing running with the lowest idle power I can manage. Also note - the data that I want to access 24/7 should easily fit onto the 2TB or so I'd get from the M.2s. Since the M.2 storage pool would always be mirrored, drive failure tolerance shouldn't be needed.

My questions are:

1. Is this a good plan? Major downsides, limitations, etc? M.2 speed limitations from lane splitting are definitely one, but I also don't have high speed requirements. The current speeds I get from the HDDs is already fine. The noise and power usage are the main things.
2. Automation recommendations? As I said above, it would nice to automate the mirroring based on drive writes to make sure the important data is always backed up, while things like logging don't make the disks spin up.
3. Case recommendations? Simpler is preferred - cases with a hot-swap backplane are actually not ideal given how the H4+ gets and distributes power. I believe I would need to buy a PSU to use a backplane. ODROID's mITX kit page goes into detail on this.

Thanks folks <3