rpi4 8GB with the radxa USB-bridged 4 port card. 4x 2TB HDD. I couldn't afford SSD. Its Ubuntu ZFS. Not over-performant, but does the job. I run a single disk ZFS detachable for periodic snapshots. Really? I like the belt-and-braces aspect of this one. 4 disks should be reasonably safe for single disk failure and I have a snap monthly, albiet all on one platter. Not enterprise-grade safe, but good-enough.

There's enough grunt left over to be my plex headend as well as long as I avoid transcoding.

I actually wanted to run FreeBSD on it, but the rpi4 wasn't fully ported when I started. In the back of my mind, it should be "safe" to convert over because OpenZFS. Which is kind-of the point.

I avoided de-dup. It burns your CPU. But I think compression is worth it, even with a lot of mp4 and mp3 and jpg content (photo and live-TV PVR archives, aside from music)

There's a lot of FUD about ZFS on small devices, how much memory you "need" -I think something said of Solaris got conflated up into a ZFS "law" about minimum memory for the ARC which just isn't really true: it may not be performant, but it works fine on smaller memory (than 8gb) systems. I chose the 8GB pi4 because I could afford it. I would have been fine on 4GB.