Bug#816858: Logical volumes on external USB disk cause boot to enter emergency shell

[Christoph Pleger]

Hello,

I have to modify my statement about a new version of lvm2. After
installing systemd again (for getting the journal messages) and rebooting,
the computer booted completely, without entering the emergency shell.
Downgrading lvm2 to the jessie version re-introduced the problem. So, the
bug is already solved in the current lvm2 version in stretch.

Regards
  Christoph