Per https://github.com/zfsonlinux/pkg-zfs/issues/221: the initramfs zfs script might overrule canmount and mountpoint options for a dataset, causing other mount operations and with them the boot process to fail.
Experienced this with Ubuntu Zesty. Xenial seems to ship with a different zfs script for the initrd.
Work around when it happens: unmount the dataset that should not be mounted, and exit the initramfs exit prompt to resume booting.
Per https:/ /github. com/zfsonlinux/ pkg-zfs/ issues/ 221: the initramfs zfs script might overrule canmount and mountpoint options for a dataset, causing other mount operations and with them the boot process to fail.
Experienced this with Ubuntu Zesty. Xenial seems to ship with a different zfs script for the initrd.
Work around when it happens: unmount the dataset that should not be mounted, and exit the initramfs exit prompt to resume booting.