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Re: r/o root filesystem?

Greg Stark <gsstark@mit.edu> wrote:
> Andreas Metzler <ametzler@downhill.@.eu.org> writes:
[mount / ro]
>> interesting files: mtab, modules.conf, 

> indeed. I seem to recall mtab can be a symlink to /proc/mounts but
> I'm not certain on the consequences of that.

It has some unwanted consequences, loop-devices don't get deallocated
automatically anymore and you cannot use the mount-option "user"
senisibly anymore, because /proc/mounts doesn't hold the name of the
user who mounted the fs and therefore only root can unmount it again.
Iirc there is more.

> modules.conf we could just skip the
> update-modules step if modules.conf isn't writable.

> passwd/shadow, /etc/resolv.conf (dhcp)

> These files should _never_ be modified by the system. They're
> configuration files for the admin to edit.

You change the users' passwords by logging in as admin and editing
/etc/shadow? (chsh ditto.) ;-)

> dhcp should be set up to modify a file in /var so
> the admin can optionally make resolv.conf a symlink to it.

>> adjtime, asound.state. - Find is your friend.

> I'm not certain about these. adjtime always struck me as misplaced
> in /etc

It probably is placed in /etc/ for the same reasons as modules.conf -
it needs to be accessible early (or late), before (after) /var has
been (un)mounted.

> and I don't know what asound.state is and don't have one,
> but from the name it certainly sounds like it belongs elsewhere.

It holds the alsa mixer settings, similar to aumixrc they are saved
automatically on start/stop. They live perfectly well in /etc as they
are plain-text files that hold configuration information.
              cu andreas
Hey, da ist ein Ballonautomat auf der Toilette!
Unofficial _Debian-packages_ of latest unstable _tin_

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