Re: Stateful system directories

[Ricardo Wurmus]

Efraim Flashner <address@hidden> writes:

> On Fri, Oct 18, 2019 at 05:08:20AM +0200, Ricardo Wurmus wrote:
>>
>> Kei Kebreau <address@hidden> writes:
>>
>> > Ricardo Wurmus <address@hidden> writes:
>> >
>> >> Kei Kebreau <address@hidden> writes:
>> >>
> <snip>
>> >>
>> >> Have you tried removing /var/lib/gdm and the contents of your user
>> >> account’s .local/share/gnome* directories?
>> >
> <snip>
>>
>> ~/.local/share/gnome-shell/application_state is a common problem.  It
>> contains some state that different versions of GNOME seem to be choking
>> on.  There are some other files like ~/.cache/gnome* that might affect
>> GNOME and prevent starting after upgrades.  It’s frustrating.
>>
>> /var/lib/gdm is the home directory of the gdm account, and it too can
>> accumulate state.  In my opinion /var/lib/gdm should always be recreated
>> on every boot.
>>
>
> Ignoring the directories in users' home directories, /var/lib/gdm has
> been a source of pain on GNOME upgrades, and we still have some problems
> with /var/cache/fontconfig and I believe there is something else with
> permissions if you switch between ntp and openntpd. I actually have the
> following snippet in my OS-config:
>
> ;; This directory shouldn't exist
> (file-system
>   (device "none")
>   (mount-point "/var/cache/fontconfig")
>   (type "tmpfs")
>   (flags '(read-only))
>   (check? #f))

Ah, neat.  A bit heavy-handed, of course, but neat :)

> While we work on fixing these does it make sense to modify some of these
> services to unconditionally recreate their home directories on
> boot/activation?

I think there’s no compelling reason to keep /var/lib/gdm state across
reboots.  When this goes wrong it’s very painful, and that’s much more
significant than any savings (e.g. in startup times) that it might bring
us.  So here’s my vote for letting the gdm service recreate its home
directory unconditionally, perhaps with a toggle to disable this
behaviour (e.g. when someone wants to use a different directory and
somehow alter GDM behaviour this way).

--
Ricardo