Ask HN: What should I use for managing hard drive arrays in 2024?

I have a use case that seems to me that it should be somewhat common but I can't find any FOSS software that does it. I want to automatically assemble an arbitrary set of physical drives into a virtual drive such that all data is stored on at least 2 drives to protect against drive failures.

RAID 1 would seem to be able to do this, but this only works with two drives of the same size (or you sacrifice extra capacity on the larger drive). There are combined schemes like RAID 10 or other raid levels, but these all have requirements on the size and arrangement of drives.

I want something where: - I can just throw an arbitrary set of drives of varying sizes at it and it figures out a way to store all data on at least two, three, or however many drives I set (ideally on a per-file basis) - It should also support easily adding and removing drives to add capacity or remove damaged drives - It should automatically reduplicate anything that was stored on a drive when it fails, if possible, and it should scream errors at me if it can't due to the array being too full - Lastly, I need to be able to mount it as a filesystem (at least over a network)

My use case is a personal nas.

What tools can do this? I have yet to find any. Since stored data can be important, the tool being reputable and mature is a major factor.