Comment 5 for bug 1569925

Do you have your root partition on iscsi, or just some auxiliary ones like /opt?

If it's the root partition, then you can't put that on an interface which is "auto" in /etc/network/interfaces -- ifupdown will tear it down during shutdown and sever the connection, explaining the hang. In this case, open-iscsi's initramfs integration will already bring it up. (Hence my question how you set this up).