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Re: unexpected changes - live-bottom/13swap running by default


Joseph Rawson wrote:
> The document I'm working on 
> is located here.  http://paella.berlios.de/quickstart-vbox.html  This 
> document might make a good example of how to test the "net" images with 
> virtualization, and may be hacked to fit on the 
> http://wiki.debian.org/DebianLive/Virtualization page.  I may do this myself, 
> when I'm done with getting paella up and running again.

Thank you, any help with improving the documentation is very welcome.

Rather than to put it into the wiki, that wiki page should me extended
and incorporated into the live-manual
(git://git.debian.org/git/debian-live/live-manual.git); let us know if
you have something to commit/merge/$whatever or if you want to do it

> Recently, with the updates, I've noticed a peculiar change that really 
> surprised me.  It seems that the new live-initramfs package searches for swap 
> partitions on the system that's being booted, and automatically enables them.  

I don't remember who and when did enabled that (or if it even came from
ubuntu), it's quite some time ago. Anyway, at the time, this was done on
purpose. The code works more or less like this:

	*If* a usable (unencrypted) linux swap partition is found
	*and* that swap partition does not contain a suspended system
	*then* it is enabled to use automatically
	*unless* noswap is given as a boot parameter.

In practise, I think that this is a very reasonable way on how to handle
it, as I can not imagine a situation where you don't want to make use of
the swap partition if you have one (except for rescue, see below). For
me, this is comparable to the behaviour of how linux threats free pages
in the ram: rather than wasting it and not using it at all, it uses it
to cache disk accesses. So I do like this setting for the desktop
oriented live flavours.

In theory however, a live system should not touch any filesystem at all,
except the one it is bootet from. I personally would also not expect any
live system to use a swap partition by default.

On the other hand, on the rescue flavour, which is primarily target at
actually do some manipulation of the disk filesystems, the absence of
noswap varies between beeing inconvenient (you have to swapoff manually
before you can e.g. repartition/format disks) and beeing distructive
(you want to do some forensic analysis on the swap partition of a given
system). Therefore, in my opinion, for the rescue flavour we really do
need to make noswap the default behaviour.

Since having different settings for the desktop flavours and the rescue
flavours sucks too, let's do a poll:

[ ] Use swap partitions automatically in all flavours (leave as is)
[ ] Don't use swap partitions automatically in all flavours
[ ] Use swap partitions for standard and desktop flavours,
    use noswap for rescue flavour.

> I would've probably never noticed this on another system, or if I was booting 
> from a live cd.  My installer, however, noticed immediately, as I couldn't 
> repartition a disk due to a swap partition already being enabled.

We will have the same problem the day we make d-i working to be launched
as application from the desktop by loop mounting the initrd, though this
is easy to handly by just swappoff before launching d-i.

> On a side note,  I've been having problems with the /etc/resolv.conf file.  In 
> my setup, mentioned above, the system that builds the live image is running 
> bind, and it's resolv.conf uses "nameserver".  I can't seem to 
> replace this file using the local-includes.

According to the code, 23networking only creates a resolv.conf if it is
not existing or empty. So the problem lies in live-helper, which is a
bug I'm looking at in a few hours.

> Thanks for making it easier to concentrate on other things! :)

That's probably the nicest compliment you can make us, thanks ;)


Address:        Daniel Baumann, Burgunderstrasse 3, CH-4562 Biberist
Email:          daniel.baumann@panthera-systems.net
Internet:       http://people.panthera-systems.net/~daniel-baumann/

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