ZFS on iscsi target fails at boot/shutdown

[Rob]

I've got a ZFS volume on an ISCSI target, once the system boots I can bring it online.

My ISCSI target shows up as:

root@test:/home/rob# lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sda 8:0 0 8.1T 0 disk

root@test:/home/rob# zpool status
  pool: data2
 state: ONLINE
  scan: none requested
config:

 NAME STATE READ WRITE CKSUM
 data2 ONLINE 0 0 0
   sda ONLINE 0 0 0

errors: No known data errors

root@test:/home/rob# df -h
Filesystem Size Used Avail Use% Mounted on
------------------- snip --------------------------
data2 3.1T 0 3.1T 0% /data2
data2/backup 3.2T 165G 3.1T 6% /data2/backup
data2/test 7.7T 4.7T 3.1T 61% /data2/test

However in the case of a system shutdown/reboot the system tries to unmount the disk after the network has been brought down which obviously fails.

When booting the system the zpool never gets imported as the 'zfs-import-cache.service' runs before the iscsi target is initiated.