Comment 18 for bug 1969247

zfs-dkms ended up working for me using LXD with the following test case:

sudo add-apt-repository ppa:ci-train-ppa-service/4831
sudo apt update
sudo apt upgrade
sudo apt install zfs-dkms

lxd init
lxc launch images:ubuntu/focal test-mysql
lxc exec test-mysql bash

# apt update && apt dist-upgrade -y
# apt install mysql-server

# touch foo.img
# fallocate -z -l 10M foo.img
# ll foo.img

-rw-r--r-- 1 root root 10485760 ...