how to boot a system with a broken but non-essential LVM VG

[Ross Boylan <ross@biostat.ucsf.edu>]

One of the disks that was in an LVM Volume Group died, as a result of 
which LVM reports an error when the system starts.  I believe because of 
the errors from lvm the boot sequence stops.  After several minutes it 
times out.  At that point a shell prompt appears.   The missing physical 
disk is no longer essential for the system to boot, and the damaged VG 
still has some good volumes in  it, so I do
vgchange -ay
which reports errors but activates what it can
and
cryptsetup luksOpen /dev/myVG/myCryptRoot CryptRoot
when I exit the shell the system boot continues successfully.  I'm using 
grub2 on amd64 and a standard initramfs for wheezy.  Note that myVG is 
not  the damaged volume group.

Is there some way I can achieve the same effect without manual 
intervention (except for the crypto pass-phrase) and without the wait 
for timeout?

Ross Boylan