systemd has always been hanging on my laptop at "Starting LSB: Raise
network interfaces....", for about 2 minutes at each boot.  Disabling
dhcp and commenting some "allow-hotplug"/"auto" lines in the interfaces
file didn't help, and booting with "systemd.log_level=debug
systemd.log_target=kmsg log_buf_len=1M" didn't reveal anything.

Finally I added "set -x" to /etc/init.d/networking and found it's the
"udevadm settle" command hanging the boot.  Its default timeout is 2
minutes.  The log is included below.  Commenting out the line makes the
system boot quickly.

I don't know what its purpose is or how to figure out why it's hanging.
Until it's fixed, I'd suggest logging a message before running the
command and logging "Configuring network interfaces..." only after it
completes.  Maybe a shorter --timeout option would be a good idea too.

- Michael