Boot from your usb stick or CD or DVD. You will boot into the LMDE live system do not start the install by clicking on the CD icon on the desktop.
Start a terminal after live boot. CTRL+ALT+t
CTRL+ALT+t
Your terminal session will be running as the user named mint, but you will need root privileges, so you must become the root user for the following steps : Become root using the following command: sudo -i
mint
sudo -i
If the logical volume you want to use has an existing file system, now is the time to create a fresh filesystem.
Warning ⚠️ This will wipe the contents from this filesystem.⚠️
My logical volume device is named lvroot1 which is a member of the volume group named vgfuji . Create the filesystem on the logical Volume:
mkfs.ext4 /dev/mapper/vgfuji/lvroot1
Mount your existing LV onto /target
/target
mkdir /target # Create a new directory /target
mkdir /target
mount /dev/mapper/vgfuji/lvroot1 /target
In the terminal start the expert live installation script
live-installation-expert-mode
When you get to the partition editor select manual installation and expert mode (now visible in expert-mode.
The installation will proceed, but will halt before completion to allow you to edit manually /target/etc/fstab so that you can add the lines to mount your root and swap filesystems.
/target/etc/fstab
You can now continue the installation, which continues till completion.