[Bug 775124] Re: Ubiquity should have a command line option to override the free space check

Tue Aug 16 07:03:38 UTC 2011

All I did for my low-disk-space ISO for Lubuntu 11.04 was to edit the
file casper/filesystem.size to contain a number lower than the one that
was there before.  I then edited one line of the file containing
md5sums, so that the Test CD Image menu item still works.  No change to
any code whatsoever was needed, just two text files in the ISO image.

This casper/filesystem.size file is supposed to contain (as a string of
ASCII digits) the size in bytes of the filesystem needed for the
installation, computed from the installed sizes of all the packages in
the default install.  What happened, as far as I can tell, is that
Ubuntu 11.04 needed a lot of additional working free space, so someone
came up with a quick fix and multiplied the value obtained from this
file by a "fudge factor" in the ubiquity code.  They then tested their
change on Ubuntu (and only Ubuntu -- not Xubuntu or Lubuntu), and it
worked for Ubuntu, so it was accepted!

In an ideal world, we should revert the  "fudge factor" patch in the
code, and allow the casper/filesystem.size file to contain the actual
size of filesystem needed for a successful installation of whatever
flavour of Ubuntu this image is.  This is clean, elegant, and easy to
understand.  Provide the correct data to ubiquity, and it does the right
thing.

In practice, I am not sure the Ubuntu folks will want to do that -- the
way things are now works fine for them :)

There are many other practical ways to solve this, including code in
ubiquity testing which Ubuntu flavour is being used, and setting the
"fudge factor" accordingly, which is "ugly" but definitely workable.
Other possibilities include a command line option to ubiquity that sets
the fudge factor, or one that disables the disk space check, or (trying
to avoid too many ugly fudge constants in the code!) looking for an
optional file under casper/ that does one of those things and which is
then present in Lubuntu ISO images but absent in Ubuntu ones...

In a related bug report (I think it started out satying teh Xubuntu web
site had bad info about disk size needs, but was really this issue in
disguise), a couple of months ago or more, I offered some time ago to
implement one of these ways forward, if someone would tell me it would
be accepted, but apparently no-one relevant read it or responded to me
about it.  Even though my work and real life time constraints are a lot
worse now than they were then, that offer stands... I don't have time to
discuss all the options, or write formal proposals and try to persuade a
group of people to agree on one, etc... but tell me a patch to fix this
in any of the ways I mentioned above will be accepted, and I'll happily
create that patch and submit a debdiff or a bzr packaging branch
containing it.

Jonathan

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https://bugs.launchpad.net/bugs/775124

Title:
  Ubiquity should have a command line option to override the free space
  check

Status in “ubiquity” package in Ubuntu:
  Triaged
Status in “ubiquity” source package in Oneiric:
  Triaged

Bug description:
  Binary package hint: ubiquity

   I downloaded the 11.04 desktop i386 iso, put it on a usb drive so i
   could it install it on my netbook, but couldnt even get past the
   install screen, because it says i need 4.4GB to install ubuntu 11.04.
   The problem is that my hard drive is only 4GB large, a common size in
   netbooks.  I have run installers for ubuntu 10.10, 10.04, 9.10 and
   9.04 netbook editions on my netbook and never had a problem before.  I
   notice that 11.04 has netbook and desktop editions combined into a
   single ISO, so maybe that is why the error happened in 11.04 and not
   before.

   Also, I notice that the install footprint of 10.10 is around 2.1GB, so
   it shouldnt be a problem running 11.04 unless they truly added 2GB of
   junk to the OS.  The problem is I just can't get past the installer.

  [i am intentionally posting a duplicate of bug https://bugs.launchpad.net/bugs/772164 because i can't change the package of 
  bug https://bugs.launchpad.net/bugs/772164 to ubiquity from netbook]

  ProblemType: Bug
  DistroRelease: Ubuntu 11.04
  Package: ubiquity 2.6.10
  ProcVersionSignature: Ubuntu 2.6.38-8.42-generic 2.6.38.2
  Uname: Linux 2.6.38-8-generic i686
  Architecture: i386
  Date: Sun May  1 20:24:28 2011
  LiveMediaBuild: Ubuntu 11.04 "Natty Narwhal" - Release i386 (20110427.1)
  ProcEnviron:
   LANGUAGE=en_US:en
   LANG=en_US.UTF-8
   SHELL=/bin/bash
  SourcePackage: ubiquity
  UpgradeStatus: No upgrade log present (probably fresh install)

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