When booting Linux into single user mode or rescue mode, you will find that unless the distro was found and enabled the logical volumes, you won't see any devices.
This makes it a fun task when you need to mount, scan, resize a partition. Below are instructions on enabling your logical volumes.
lvm vgchange -ay
It's as simple as that, now you should see your normal LVM devices in /dev
By justin, January 24, 2015