You can, although you need to replace all the drives in the pool. You can swap one, wait for resilver (or for a month, if you're in a budget), do the next one... And once you replaced every drive, you do like this:

https://www.ateamsystems.com/tech-blog/expand-zfs-to-use-lar...

Few years ago, I needed exactly that, and it didn't work.

I guess I'm not alone: https://www.google.com/search?q=zfs+autoexpand+not+working

>You can't replace drives with bigger ones and expand the pool.

Yes you can. That's exactly what the 'autoexpand' property is for. It's odd how this kind of thing floats around on the internet.

Just because there's a property doesn't mean that it works. It floats around on the internet, because that's the experience people have.

It works just fine. I've upgraded vdevs this way several times, and it worked without a hitch on every occasion.

It didn't for me; in the end, I backed up the files, scraped the machine and put the drives into Synology box.

So take it as an piece of the puzzle why is Synology more popular.