Have you tried a restore? A non-differential smap snapshot should be fine, but differential snapshots would make a restore difficult to impossible.

A zfssend and zfsrestore with a differential snapshot would be more traditional. If one put mbuffer in the middle, it would even be fast.

Kinda related: what if I install something like Debian/Ubuntu on it? Can I still use the NAS hardware in the same way?

This question confuses me. Debian and Ubuntu can be setup to be NASes.

NAS is a description of a mid-level function that various software provide a part of.

Various file systems and volume managers can provide snapshots and rollbacks. To aid your research LVM, ZFS, and many others support snapshots.

There are various ways to then expose the formatted space to the network. To aid research NFS, SMB, and iSCSI are options.

Anyway, I hope this is helpful to someone.

I wonder if the specifics of the hack would make backing up elsewhere fail. Possibly by spreading the hack to new machines.

In any case, testing backups is important.

Also consider rubber feet.

Does the sound correspond to the power draw?

Power at idle and with Home Assistant running. I assume the noise is when the power draw is higher, but that is unclear.

To me, it sounds like the HDDs. What is anything is using them? Often raids will scan then entire disk at initial setup.

When looking at the drives, check the “disk writes per year”, as that will give an estimate of what the vendor thinks the life will be.

Seagate brands some good ones. I had a few that went years and none failed. Samsung makes some PCI monsters which are likely overkill.

I would only get new and register then ASAP for the warranty, or cheap from a trusted friend.

Baculum for Bacula https://www.bacula.lat/baculum/?lang=en

No. I do not suggest anyone do any of these.

Others have given the direct answer of “no”. Cheap is relative, so here are some options that assume a higher value of “cheap”.

DIY solar panels and DIY flywheel generator.

Professional solar panels on your dwelling and professional whole house battery storage. (Fix the issue by fixing a larger issue.)

Buy an electric car that can power the equipment. A Ford Lightning (there are other choices) in the garage, that never moves, will solve the issue of swapping batteries. Check junkyards for a used one.

Move closer to a power plant, while also ensuring a minimum power line distance.

Move closer to something with a very high up time requirement. (A hospital may have generators, but they may also have a requirement for their power to stay up nearly always.)

Use AWS or co-hosting to make power not your issue.