I have written a couple articles about this here http://blog.ls-al.com/ubuntu-on-a-zfs-root-file-system-for-ubuntu-15-04/ and here http://blog.ls-al.com/ubuntu-on-a-zfs-root-file-system-for-ubuntu-14-04/
This is a quick update. After using virtualbox to export and import on a new machine my guest did not boot up all the way. I suspect I was just not seeing the message about manual/skip check of a file system and that the fstab entry for sda1 changed. Here is what I did. On bootup try āSā for skip if you are stuck. In my case I was stuck after a message about enabling encryption devices or something to that effect.
Check fstab and note disk device name.
root@ubuntu:~# cat /etc/fstab/dev/disk/by-id/ata-VBOX_HARDDISK_VB7e932a52-ef3c41b0-part1 /boot/grub auto defaults 0 1Check if this device exists.
root@ubuntu:~# ls -l /dev/disk/by-id/ata-VBOX_HARDDISK_VB7e932a52-ef3c41b0*ls: cannot access /dev/disk/by-id/ata-VBOX_HARDDISK_VB7e932a52-ef3c41b0*: No such file or directoryWhat is the correct device name.
root@ubuntu:~# ls -l /dev/disk/by-id/ata-VBOX_HARDDISK*lrwxrwxrwx 1 root root 9 May 9 15:38 /dev/disk/by-id/ata-VBOX_HARDDISK_VBb0249023-5afef528 -> ../../sdalrwxrwxrwx 1 root root 10 May 9 15:38 /dev/disk/by-id/ata-VBOX_HARDDISK_VBb0249023-5afef528-part1 -> ../../sda1lrwxrwxrwx 1 root root 10 May 9 15:38 /dev/disk/by-id/ata-VBOX_HARDDISK_VBb0249023-5afef528-part2 -> ../../sda2Keep old fstab and update with correct name.
root@ubuntu:~# cp /etc/fstab /root
root@ubuntu:~# vi /etc/fstabroot@ubuntu:~# syncroot@ubuntu:~# diff /etc/fstab /root/fstab1c1< /dev/disk/by-id/ata-VBOX_HARDDISK_VBb0249023-5afef528-part1 /boot/grub auto defaults 0 1---> /dev/disk/by-id/ata-VBOX_HARDDISK_VB7e932a52-ef3c41b0-part1 /boot/grub auto defaults 0 1Try rebooting now.