[Gloucs] Migrating to Ubuntu whilst retaining old files/drives

[Andrew M.A. Cater]

On Thu, Feb 15, 2007 at 12:02:49PM -0000, Andrew Oakley wrote:
> 
> I wish to migrate my home Linux server from Fedora Core 2 (commandline
> only install, no GUI) to the latest LTS Ubuntu (with GUI), and need some
> advice.
> 
Why do you need a GUI - use Debian Etch and stick with command line.

> The server is used as a Samba fileserver using two pairs of software
> RAID1 mirrors, a Samba printer server, an Apache web server for test
> projects only, an iptables-based NAT router/firewall and Sendmail SMTP
> server which acts as a backup MX for a number of domains.
> 
> By "migrate" what I mean is completely destroy and re-install from
> scratch, but I wish to retain the files on the Samba share, which are
> spread across /dev/md0 and /dev/md1 . There are only four drives and I
> don't have a spare.

320GB external hard drive is now less than £80. Rsync your data to this
before you start. Use it periodically thereafter to take backups.
I have one for my Debian mirror that I could lend you.

> 
> / is mounted on /dev/md0 together with half of the shared files.
> 
> So far, the best way I can think is:
> 
> * Take a backup of /dev/md0 onto DVDs
> * Take one drive out of the /dev/md0 pair, giving me Spare#1

See above.

> * Install Ubuntu on Spare#1 using ext3 filesystem (so as to retain
> compatibility with software RAID)

Debian partitioner should let you do this fine. Do you want a DVD on 
Tues?

> * Boot from Spare #1
> * Copy all the files over from /dev/md0 to Spare#1
> * Destroy /dev/md0, giving me Spare#2
> * Create a new /dev/md0 based on Spare#1, then hotadd Spare#2 to that.
> 
> Will this work? Any better suggestions?
> 
> What about the users and permissions on the old filesystem? Will I be
> able to access all the files on the old /dev/md* devices (ex-Fedora)
> from the new Ubuntu OS? Will I need to ensure I re-create all the users
> and passwords identical to the Fedora OS, or can I copy vast swathes out
> of /etc/passwd and just pray?
> 

This is a nightmare. Different distros have different starting points 
for their users as against their system level users e.g. users start at 
1000 in Debian but may start at 500 on a Red Hat based distro. You're 
better backing up only the files you want to keep from the Samba file 
system and /etc so that you get your Sendmail config for reference. 
You're actually quicker to throw away absolutely everything from a 
three year old system if you're switching distros and start from scratch 
IMHO. For myself, I'd also throw away Sendmail and use Postfix - but, 
given your job title, I'll defer to your knowledge and requirements :)

If you were to software raid5 your existing disks, would you have enough 
diskspace?

> ps. Bear in mind that the Fedora Core OS is a commandline-only install,
> and I have NEVER used a Linux GUI. If the whole thing can be done via
> the terminal, I'm a much happier chap.
> ___________________________
> 
> Andrew Oakley
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