Got brand new HP Proliant DL360 Gen9 issue booting into proxmox

[esi_y]

When it comes to BTRFS as a choice in PVE for guests, I actually prefer QCOW2 for VMs (this is not PVE specific preference, anything QEMU/KVM, really). If you have QCOW2, it is counterproductive to have it on anything copy-on-write (BTRFS or ZFS), you can use its snapshots (which are superior). BTRFS does not have equivalent of ZVOLs. But for me on ZFS, they are buggy, so I am back to QCOW2 (or RAW) on ordinary dataset.

So yes, confirmed, on plain install now upon selecting BTRFS, it gets you BTRFS subvolumes for VMs and the disks are stored there as raw files, e.g. var/lib/pve/local-btrfs/images/100/vm-100-disk-0/disk.raw ... it is this setup the YT video maker was benchmarking I believe.

I actually believe the bad results, it is after all copy on write filesystem. What I do not believe are the very good benchmark of ZFS - they must be on par (both much worse than regular filesystem).