Speeding up the installation by adding --force-unsafe-io to dpkg?

[Petter Reinholdtsen <pere@hungry.com>]

I saw an idea floating around that telling dpkg to not call fsync() for
every file in every package it installs on the hard drive would make the
installation faster, and decided to see if this would help in Debian
Edu.  Here are some notes from my testing.  In short, not much
improvement was seen and I just mention it here to have that fact
documented.

I tested using a DVD image booted from a USB stick.  My test machine is
a Dell Latitude D505 (very old x86 based machine), and I installed the
standalone profile.

First I did a normal installation, and recorded the time between the two
hooks were executed using this command on tty2 while the finish-install
dialog was shown:

  grep edu /var/log/syslog |grep hook

The initial duration was from 09:39:10 to 10:00:38, ie 1288 seconds.

The I tested with force-unsafe-io enabled.  While the base system was
being installed, I went to tty2 and ran this command to enable it:

  echo force-unsafe-io > /target/etc/dpkg/dpkg.cfg.d/edu

The duration between the two hooks were on the next run from 12:09:47 to
12:31:03, ie 1276.  The improvement were thus 12 seconds or 0.9%.

So I guess we will have to look for another way to speed up the
installation. :)
-- 
Happy hacking
Petter Reinholdtsen