I have been using ZFS as the boot drive with Proxmox. It’s working great, but after the initial install I find that the boot hangs and leaves me at the initramfs prompt without the pool imported.

We can import the pool manually.

zpool import -R / -N rpool

Then continue booting with ctrl+d, but the problem occurs again at the next boot.

This solution on the forums solved the problem for me.

echo -n " rootdelay=15" >> /etc/kernel/cmdline
pve-efiboot-tool refresh

Then reboot.

shutdown -r now