Mailing List Archive

Disk image? and other general questions
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

--
__________________________________________
Jean-Sébastien Guay jean_seb@videoton.ca
http://whitestar02.webhop.org/


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Re: Disk image? and other general questions [ In reply to ]
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

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Rikard Johnels email : rikjoh@norweb.se
Web : http://www.rikjoh.com
Mob : +46 735 05 51 01

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gentoo-alpha@gentoo.org mailing list
Re: Disk image? and other general questions [ In reply to ]
On the fine day of Mon, 04 Oct 2004 21:50:00 -0400
Jean-Sébastien Guay <jean_seb@videotron.ca> said very eloquently:

> 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).

You can do a drive image as someone else already commented. What works
really well for me is to use an extra partition or hard drive for the
secondary OS that you are trying out. That way you never are overwriting
your main OS so you don't have to worry about losing it. And you can
jump back to your normal configuration by just booting into that
partition instead.

I always try and remember when partioning a disk to leave an empty 3-4
gig partition for this purpose. It really comes in handy.

Also if you do things this way it's also possible to install gentoo from
the other OS (using chroot), so you always have access to the web, etc.
while you are building the gentoo system. Then your main system
is not down for any long length of time. There's some documentation
about this on gentoo's site; I believe it's in the"alternative
installation howto".

I just went through this with rebuilding my Alpha gentoo installation.
If you want any more details let me know.

> Also, somewhat unrelated -- How does Gentoo handle configuration
> files?

There's an app that let's you interactively merge the changes. It's not
fancy (it's just text based) but it sounds more flexible than
what you are talking about with debian.

AZ--

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