Why btrfs instead of zfs? Wouldn't it make sense to be able to use ZFS-only features?
I've been trying to do this with ZFS for a while now, but I'm running into bugs that aren't currently solvable. For example, zfsbootmenu doesn't work when used with the pre-compiled Void EFI image; no snapshot is visible at boot due to modifications made by the Proxmox VE installation. Creating the EFI image from scratch makes it even worse. Zfsbootmenu was developed primarily for Void; it works with other distributions, but I haven't found a solution for this particular problem.
Another point: I'm using this configuration on a laptop, and ZFS is extremely slow at startup, shutdown, and during daily use. The CPU load is between 5 and 10% higher. The same issue with RAM persisted. Even after trying to modify the ARC cache to minimize RAM usage, I experienced crashes. I had to allocate a minimum of 4GB to ARC for it to function, so ultimately, whithout any VM, RAM usage quickly climbed to around 8GB.
I couldn't get the laptop to boot even if a disk failed. If you use ZFS with Proxmox tools, it won't boot if the boot disk is faulty; you have to use the command line to resolve the problem. Without Proxmox tools, it's also impossible because once the ZFS partition is degraded, there's no way to boot from a mirror (it works on a RAIDZ1 array with three disks, but not in a mirror configuration, I don't know why).
There are other issues as well, but basically, that's why I chose BTRFS instead of ZFS.
If someone manages to solve the three biggest problems I mentioned, I would obviously use ZFS, but currently it's not possible in my case.
The reason I started this project, in case anyone asks, is that I had a problem with an SSD in late 2025 (both the boot and system SSD), and I wasted time reinstalling everything (no data loss).
