I used to (over a span of about 4 years now) just rely on a RaidZ2 (ZFS) pool (faulted drive replacements never gave any issues) but I recently did an expansion of the array plus OS reinstall and only now am I starting to incorporate Docker containers into my workflows. The live data is in ~ and nightly rsynced onto the new larger RaidZ2 pool but there is also data on that pool which I’ve thus far never stored anywhere else.
So my answer to the question would be an off-site unraid install which is still in the works. This really will only be that. A catastophe insurance. I probably won’t even rely on parity drives there in order to maximize space since I already have double parity on ZFS.
As far as reinstallation goes, I don’t feel like restoring ~ and running docker compose for all the services again would be too much of a hassle.