Install Debian over Ubuntu using same home partition

Question

I'm interested in changing from Ubuntu to Debian. I currently have 12.04LTS installed on its own boot partition which is separate from the /home partition.

I would simply wipe the Ubuntu partition and install Debian and modify the fstab file to mount my home and swap partitions.

What types of problems would I come across? Which would be a better choice the testing or unstable branch?

Solution 1

Make sure that the new distribution supports the storage that you've set up, including

• partitioning type (PC, UEFI, …)
• RAID or encryption layer (mdraid, dmcrypt, …)
• volume layer (LVM, …)
• filesystem (ext4, btrfs, zfs, …)

Going from Ubuntu 12.04 to Debian wheezy or even squeeze, I don't think you'll lose anything, so in your case you won't run into any problem.

Be sure to back up /etc from your Ubuntu installation. In particular, you'll need to restore the user and group IDs from your existing installation, for all your users that have a home directory in /home. Files are associated to user and group IDs, not names. The association between user IDs and names lives in /etc/passwd, and for groups in /etc/group. If you copy entries from your backup to your new system, be sure to copy the corresponding entries in /etc/shadow and /etc/gshadow as well.

If you want to retain your machine's SSH identity, copy /etc/ssh/*key* from the old installation.

If you've set up LUKS disk encryption with a key file, be sure to keep the key file.

Whether to choose stable, testing or unstable is up to you, it depends how much you value security and stability vs having the latest software (complete with the latest bugs).

Solution 2

Good choice! You might want to read Debian documentation on choosing. There is much more definitive information from the Debian website, but an excerpt from the documentation summarizes it well:

If security or stability are at all important for you: install stable. period. This is the most preferred way. If you are a new user installing to a desktop machine, start with stable. Some of the software is quite old, but it's the least buggy environment to work in. You can easily switch to the more modern unstable once you are a little more confident. If you are a desktop user with some experience in Linux and does not mind facing the odd bug now and then, use unstable. It has all the latest and greatest software, and bugs are usually fixed swiftly. If you are running a server, especially one that has strong stability requirements or is exposed to the Internet, install stable. This is by far the strongest and safest choice.

Trouble with the home partition will be very minimal to maybe non-existent. The UID/GID of the "old" user/s might change; but, that's a simple fix: just chown/chgrp to the new UID/GID.

You can go from stable to testing to unstable, but not backwards. If stable suites you and your hardware, stop there. If not, switch to unstable. The testing branch sometimes takes a long time (months) to fix anything that breaks.

Solution 3

You may have to mess with some symlinks to get the user folders lined back up, but that theoretically should work fine... also be sure to check all the users' bash profiles (/home/someuser/.bashrc) to account for possible remaining references to removed software.

With some of the more minimal distros like Slackware or Arch, you make the root filesystem first, meaning there shouldn't be too many ties between /home and the OS, though I feel like you should wait for someone more qualified to answer.

Solution 4

At this very moment in time, you won't get much advantage over testing in unstable because of the code freeze for the next release. Both versions currently have Gnome-Shell 3.4, for example. So why not try testing for the time being and see how much you like Debian. You can always upgrade to unstable later if you like.

View more solutions

Comments

[Andrea de Marco]

Thanks, Do you recommend that I backup any folders beside /etc? possibly /usr? @Gilles

[Gilles 'SO- stop being evil']

@winchendonsprings Backing up /usr is useless, except /usr/local if you've put stuff there (you can copy that wholesale). I recommend backing up /var, just in case; it's a bit messy in terms of what to back up and what can be thrown away, with both things like /var/cache (entirely disposable as the name suggests) and /var/mail (vital if you receive mail locally), /var/spool/cups (contains only active printing jobs) and /var/spool/cron (contains users' crontabs).