[Pkg-sysvinit-devel] Announce parallel booting to debian-devel-announce?

[Petter Reinholdtsen]

[Petter Reinholdtsen]
> I've started on an announcement text on
> <URL: http://wiki.debian.org/LSBInitScripts/DependencyBasedBoot/announce-2010-05-parallel >.
> Please help me to get the draft ready.  I hope it can be sent on
> Wednesday or Thursday.

I complete a draft just now.  The text now look like this.


send to debian-devel-announce@

Subject: Debian enabled parallel booting by default

Another small step in the improvement fo the Debian boot system was
taken last weekend, when sysvinit version 2.88dsf-5 was uploaded. It
concluded an almost 8 year effort to get the Debian boot system to run
boot scripts in parallel. The parallel booting is enabled by default
in unstable at the moment, and will enter testing in 7 days, unless
some serious problem is found.

Running init.d scripts in parallel was proposed at Debconf in 2002[1],
and I started working on in early in 2005 after finding the insserv
package from SuSe capable of reordering the boot sequence based on
headers in each init.d scripts. The header format is specified in the
Linux Software base. Getting this to work required us to add the
header to all init.d scripts in Debian, affecting around 850 packages
in the archive. This was a release goal for Lenny, and enabling
dependendy based boot sequencing using these headers has been possible
for a some years now. Using dependency based boot sequencing by
default was enabled in unstable and testing last summer, and the
quality of the init.d script dependencies have improved as a result of
this.

  * http://alioth.debian.org/docman/view.php/30730/38/debconf2-initscripts-bkg.pdf

The next natural step is to use the dependency information to run the
scripts in parallel, and this is now enabled when the machine is using
dependency based boot sequencing.

There is still more work left to do. Here are some issues I want to see
implemented:

  * The early boot system need to trigger on kernel events, to make sure the
    devices needed (as in USB or SCSI hard drives to be mounted at boot) are
    available when fsck need them. The most promising candidate for this is
    upstart, but the newcomer systemd look interesting too.
  * Several of the scripts currently started from /etc/rcS.d/ should be moved
    to /etc/rc[1]5.d/ to improve the single user mode in Debian, but also to
    increase the amount of concurrency during boot.
  * Shutdown speed can be improved by removing scripts only killing their
    daemon from /etc/rc[06].d/ and leaving it to the sendsigs script to kill
    all of them at the same time instead.

Happy hacking,

The sysvinit maintainers


Comments, protests, corrections and improvements are most welcome.

Happy hacking,
-- 
Petter Reinholdtsen