I'm impressed by what I see.

The differences aren't as big as they seem ...

I am in the planning stages of deploying Proxmox to a 2tb|2tb + 3tb|3tb zfs array and after a bunch of reading, I understand that zfs recordsize and qcow2 cluster_size shoud match each other exactly.

Proxmox Linux. ZFS root, 50GB for rpool. Single disk. Almost all of rpool capacity is used, and I don't know where. There were snapshots, but I've deleted them. Code: # zpool list -v NAME SIZE ALLOC ...