Copy Server/Applications Settings and Data to New Ubuntu Install

Question

So here's where I'm at:

I've had Ubuntu Server 12.04 install on a 250GB drive for a while, and I've spent some time getting it configured properly with a number of programs. I want to migrate the data/config to a bigger drive, but instead of using dd or Clonezilla (like a normal person), I started with a clean install on the new drive - I wanted to change the main admin username, install without home folder encryption (which I removed by hand from the old drive), and stop using LVM for a single-drive machine.

So here's where I'm at: I have Ubuntu Server installed on the new disk, and the main partition from the old disk is currently mounted at /mnt/old_drive, so I have access to all the files and things. I also have a dump list of all the packages I installed on the old machine.

So here's my question: how much of this stuff can I just copy over directly, reboot and have it work? Just /etc? I've got a couple things, like MySQL and PostgreSQL DBs, that I'm not sure if I can just copy over with cp.

Or would I be better off installing each package and configuring/migrating them individually? I think the fact that I change the admin username on the new install may add a wrinkle (or not).

Edit: I also do know I need to edit fstab rather than copying it over.

Answer 1

If you are up for the learning experience, try backing up your current new /etc and then copying the files from /etc incrementally from the old drive to the new drive. As long as you arent changing versions of packages most software will gracefully handle that. There are however a few files that wont work, /etc/fstab being one prominent example. Also be careful with files in /etc/udev (as this will most likely contain hardware specifics, like MAC addresses of your networking hardware, etc)

If however you want to be on the safe side, just don't copy the files and manualy redo the changes.

Of course you could also use a tool like kdiff3 or similar to compare the differences and visually migrate the settings.

I personally would assume that the fact that you changed the admin username (I presume you mean user which you will be mainly using the computer with) might indeed cause some trouble, specifically with the SQL DBs as they tend to have the access rights stored somewhere within the DBs, however this could possibly be solved with an automated search and replace SQL statement. Additionally run grep -R with your old username over your old /etc directory and see if you get any hits other than the usual (passwd, shadow, groups) and improvise ;-)