It was just an example with easy to reason about numbers. You could do the same thing with 2-disk redundancy.

> https://www.digistor.com.au/the-latest/Whether-RAID-5-is-sti...

I've seen a lot of articles and blog posts like this, but their numbers never seem to make sense. It says that reading through a 4-disk 8 TB array you only have a 15% chance of success. I have full-array BTRFS scrubbing scheduled monthly, according to this my array should have reported errors many times a year...

And of course, no matter what, no form of RAID/ZFS is a backup.