I had a dual boot system with Debian Sid and some proprietary other OS (*cough* wind*cough*s). The Debian installation is installed on 3 encrypted partitions, with LVM on top of them. I installed Linux Mint 13 next to the Debian system (also on the encrypted systems), so that I now have a triple boot setup: Linux Mint 13, Debian Sid and Windows. I thought it would be interesting to document how I did it, and what issues I ran into.

Before I started, I uninstalled all kernel-image-* packages from my debian system, except the one corresponding to the kernel I was actually using. This will eventually reduce the number of choices in the grub boot menu when finished. I backed up all in /boot, to be able to recover the original dual boot configuration in case of something going wrong. (Of course you should backup your whole system, and not only /boot, but hey, we all know how this goes, don't we.)

I downloaded the 64-bit-live-DVD for Linux Mint 13 with Cinnamon, and I put it on an USB-stick using unetbootin. Then I booted from the USB stick.

The first thing to do, was enabling lvm, and decrypting my encrypted partitions:

apt-get install lvm2
modprobe dm-mod
cryptsetup luksOpen /dev/sda6 crypt_sda6
cryptsetup luksOpen /dev/sda7 crypt_sda7
cryptsetup luksOpen /dev/sda8 crypt_sda8
lvscan

sda6, sda7 and sda8 are my encrypted partitions. The lvscan showed that all my logical volumes were found and active, so I didn't have to vgchange -a y the volume group.

Now I had to create a new partition for the root file system of my Mint installation. I had more than 100 GB left on my volume group, so this was not a problem.

lvcreate -L 20G -n mint-root vg-debian
mkfs.ext4 /dev/vg-debian/mint-root

(My volume group is called 'vg-debian', because it was created this way by the debian installer. This doesn't make sense with multiple distro's installed onto it, but what's in a name anyway.)

To be sure, I ran partprobe, and then I started the mint installer. First I had to choose the partitions to use. For /boot, /home and swap, I took the existing ones from the Debian setup. As root partition, I chose the freshly created mint-root. I marked only the latter to be formatted.

The installer complained about system partitions not being empty, and it told me it might erase them. I guess it was referring to the /boot partition, but as will turn out, most of the files on there will just stay where they are.

After the configuration of the partitions, the installer started copying files, and asked me where I live. I chose 'Brussels', and then the installer froze. Partly. The progress bar of 'copying files' was moving, but for the rest nothing happened. I waited until the progress bar was completely full, but it kept being unresponsive. So I just killed the installation process, and I was left with a half-installed system. Exciting :-)

Luckily I was installing from a live CD, so I got a browser to search for help. On the Mint Forum I found a post which described more or less what the Mint installer actually does. So I could continue the installation process manually. My mint system appeared to be mounted under /target. First of all, I edited /target/etc/crypttab, and put the following in:

crypt_sda6    /dev/sda6       none    luks
crypt_sda7    /dev/sda7       none    luks
crypt_sda8    /dev/sda8       none    luks

This is needed to get the information of the encrypted partitions in the initrd. Then I chrooted into the new system, and installed the necessary packages for encrypted lvm:

chroot /target
mount -t sysfs none /sys
mount -t proc none /proc
mount -t devpts none /dev/pts
apt-get install cryptsetup lvm2

I set the root password:

passwd

and created a user.

adduser johan2

Initially I gave my user a different user name (johan2) than on the Debian system (johanv). This will create a new home directory. Then I just rename the new user:

usermod -l johanv johan2

Now I have a user johanv, with home dir /home/johan2. I do this because I typically have the following directory in my /home file system:

• /home/johan1 (home directory for system 1)

• /home/johan2 (home directory for system 2)

• /home/johan-shared (files I share between the two systems)

In johan-shared, there are my settings for e.g. mutt and pidgin, and my develop-subdirectory. In the actual homedirs (johan1 and johan2) I have symlinks to the files in johan-shared. Whenever I switch to another distro, and I notice I need something from my previous homedir, I move these files to johan-shared, and put links in all homedirs.

At last I installed the bootloader: (I just accepted the defaults)

dpkg-reconfigure grub-pc

Moment of the truth: rebooting into the fresh system.

umount /dev/pts
umount /proc
umount /sys
exit
umount /target/dev
umount /target/home
umount /target/boot
umount /target
reboot

The grub menu was shown, but when I booted into Mint, my screen showed some noise, and nothing else happened. Apparently the system was waiting for the password of the encrypted disc, but it didn't show a message that told me so. So I just entered the password, and I saw the disc activity indicator flickering. I had to enter the password two more times (because I have 3 encrypted volumes), and finally I had a running Mint system. More or less.

First problem: the mouse wasn't working correctly. When I clicked somewhere, the actually click was registered a little to the left of the mouse pointer. This was an annoying problem, but quickly resolved after installing the software updates. I tend to do this via the command line:

apt-get update
apt-get upgrade
apt-get dist-upgrade

After a while a second problem appeared. The system froze. But this is no new problem for me. I have an NVidia Quadro FX 1800M video card, which makes the free nouveau driver crash from time to time. This is a problem I have noticed on different distributions. So I installed the freedom hating nvidia driver (press the ‘super key’ (AKA the win***-key), enter 'driv', and the menu item 'Additional Drivers' will pop up. This tool will automagically install the driver for you). Installing the evil driver fixed the problem of not prompting for passwords as well.

One last thing left to do: make the old Debian installation available via the grub menu. For this, I needed the backup of my old /boot, to look at the original /boot/grub/grub.cfg file. I copied the Debian GNU/Linux entries in there, and appended them under /etc/grub.d/40_custom. And then:

update-grub

This appended entries for Debian at the bottem of the grub menu, which now allows me to boot into my old system as well. It also seems to create some extra entries, which claim to start Mint with the old Debian kernel files. I didn't try to boot these (yet).