Bad install experience using Jigdo ISOs

On Wed, Jan 31, 2007 at 09:24:14PM +0200, Justin Hartman wrote:
> About a month ago I downloaded the Debian Testing CD1+2 using Jigdo. I
> have never used Jigdo before this but I liked the concept of what
> Jigdo was all about. Everything went off smoothly and I had no errors
> while getting these two ISOs.
>
> Today for the first time I tried to install Etch from these two CDs
> and everything went well up until installing the base system. During
> the base installation there were about 6 or 7 files which the
> installer told me were corrupted and this ultimately led to me being
> unable to install Debian with these CDs.
>
> As I had already partitioned and formatted the drive in the previous
> step I lost everything and now had no OS to install on the machine. In
> the end I pulled out an old Ubuntu 6.06 disk I had lying around just
> to get the computer up and running.
>
> Now a couple of things bugged me about this which might pose as an
> opportunity to improve the whole installation process:-
>
> 1. Assuming my ISO was corrupt from using the Jigdo system surely the
> installer should have picked this up before I committed to cleaning my
> hard drive? Is there not a way for the installer to pre-check the
> base-installation package files as a precaution?

I believe there is a "verify disk" option in the installer main
menu. You have to "back" out of the install process to get to the
menu.

Your assumption above can be checked with md5sum .iso and comparing it to the readily available md5sums
online.

>
> 2. Prior to installing the base system the installer sets up DHCP
> connections which if connected to an Internet connection in theory
> would provide the installer with access to the Internet. Assuming all
> of this is true would it not make sense for the installer to attempt
> to download any corrupt packages from a mirror rather than failing and
> leaving a users install un-usable? Later on in the install process you
> setup a mirror and the installer downloads packages needed so it seems
> silly that it doesn't do the same for corrupted packages.

only works if the corrupted packages are not somehow required to do
the download.

>
> I'm less upset about the install failing as I am confused. The base
> system is the core and anything can be built on top of the base
> install which is why there should be failsafe checks in place to try
> and prevent a corrupted install. If my CD2 was corrupted I wouldn't
> have minded as I would have the base and I could then download the
> latest files from the net anyway.

I don't know why the cd doesn't automatically check itself, although,
if you've got a known good cd doing multiple installs, having it check
itself every time would be a pita.

I don't diagree with you that some sort of failsafe checking would be
nice, though there are currently so many install methods it might be
prohibitively complicated to cover them all. Maybe a nice reminder
that pops up before the partitioning portion would be a good way to
go. Something like

"You are about to pass the point of no return in your install and you
have not yet verified the checksums for this installer image. Would
you like to do so now?"

might be just the ticket.

A

Hi Justin,

You might want to send an installation report:

http://www.debian.org/devel/debian-installer/report-template

So the developers get to know about your experience. Also your
suggestions should be included.

Until eventual changes happen you can check the integrity of the iso
respectivly the files yourself. On a linux box my commands to do so
look like this:

# mount -t iso9660 -o loop /path/to/iso /mnt
$ cd /mnt
$ md5sum --warn --status --check md5sum.txt && echo SUCCESS!

Regards
Marcus