I found it just recently when upgraded my VM images storage and BTRFS was still significally slower on HDDs using Ubuntu 16.04. Though I only compared it to EXT

I found it just recently when upgraded my VM images storage and BTRFS was still significally slower on HDDs using Ubuntu 16.04. Though I only compared it to EXT4 on LVM with QCOW2 + backing files. Any idea if there was newer performance comparison for VM storage?