Re: Disk image? and other general questions

On Tuesday 05 October 2004 03.50, Jean-Sébastien Guay wrote:
> Hello,
>
> This question might strike you as a bit bizarre, but here goes anyways.
>
> I have an Alpha XL currently running Debian. I would like to see how
> Gentoo works on it, but I would especially like to have the option to
> back out and go back to my running system if it doesn't work (or I don't
> like it, though I doubt that frankly). Is there a way of making a
> complete "disk image" of my currently running system? By "disk image", I
> mean all files, permissions, filesystem configuration, partitions, etc.
> If possible, I would like to be able to put that image onto a network
> drive (since the current drives on the system don't have the space to
> fit such an image).
>
> If I was able to do that, I would be able to restore from that image if
> something were to go wrong.
>
> The Alpha is currently my household's gateway/firewall, web server, file
> server, etc. That's why I need to know that even after a few days of
> compiling sources for Gentoo, I can go back at any time.
>
>
> Also, somewhat unrelated -- How does Gentoo handle configuration files?
> I mean, I know a bit about the portage system, the emerge command that
> updates all the packages on your machine. But that raises the question,
> what happens if I had to massively modify a certain software package's
> config files, and then that package is updated and the config file has
> new options, a new format, whatever. Does it do it the way Debian does
> it (which is one reason I'd like to move away from Debian -- it just
> gives you the option to keep your file, or overwrite with the new one,
> no in between)? Or does it do it in a smart way, for example letting you
> merge differences "à la" CVS?
>
> Thanks in advance. I'd very much like to try out Gentoo, but if
> possible, with as little risk as possible.
>
> J-S
If you have another linux box running, I would do the "backup" via NFS.

1. Export a directory on the second linux (with ample space).
2. Boot the Alpha into a rescue system via a cd
3. Setup the networkcard and ip-adress
4. Mount the NFS share on lets say /mnt/
4. do a "dd if=/dev/sda of=/mnt/diskimage.img" 
 (if you have the instalation on /dev/sda)

That would produce (aside from lots of network traffic) a huge image of your 
current setup.
In case of emergency, just redo the steps above but change the dd to 
"dd if=/mnt/diskimage.img of=/dev/sda"

There are probably nice switches to dd to make it smaller.
I wouldnt use zip or any other compressors incase you get an error. 
You might not be able to recover the image...

-- 
         /Rikard

------------------------------------------------------------------------------------
Rikard Johnels          email   : [email protected]
                        Web     : http://www.rikjoh.com
                        Mob     : +46 735 05 51 01

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