Slashdot/IBM: How To Speed Up Linux Booting

[Michael Biebl]

2007/4/10, Miriam Ruiz <little_miry at yahoo.es>:
>
> --- Marco d'Itri <md at Linux.IT> escribió:
>
> > On Apr 10, Erich Schubert <erich.schubert at gmail.com> wrote:
> >
> > >  That's why it's non-trivial, the requirements should be documented and
> > >  a mirgation document should be written. And then we need a couple of
> > >  people to do a hackfest to write as many new init script as they can
> > >  do in one day.
> > Writing a new init script for each init system obviously does not scale.
>
> The idea is then to make some kind of meta-script which would be then
> converted to all the rest of the systems, such as the way menu entries are
> handled? Will it be possible to design one for all?

I don't think this is possible. upstart, initng and sysvinit et al
have completely different paradigms (event based vs. dependency based
vs chronological order).
I also don't think it will be possible to translate existing
initscript (shell scripts) in an automated fashion into upstart jobs
or initng ifiles. Shell syntax is simply to complex

What we should push for as first step though, is making sysvinit
non-essential (I already wrote about this topic wrt upstart on the d-d
ml last year) and introducing an new package, let's call it "initcore"
for now, which provides the core infrastructure, like
update-rc.d/invoke-rc.d, and make that package essential.
This package could then have a dependency on "sysvinit | initsystem".
Packages like upstart could then have a Provides initsystem. If one of
the replacement initsystem proves to be the most promising one (which
imo is upstart atm) we can switch the default later on.

As a next step we should scan existing dpkg maintainer scripts/init
scripts and logrotate files and check if they use invoke-rc.d properly
or call /etc/init.d/$scripts directly and file bugs against these
packages.
We will need this so replacement init systems can divert
invoke-rc.d/update-rc.d.

As maintainer of upstart, I already thought about this topic alot. As
soon as I have some spare time, I'll write something more detailed.

Cheers,
Michael


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