Ubiquity - setting a separate /home by default

Colin Watson cjwatson at ubuntu.com
Tue May 13 23:33:45 UTC 2008

On Tue, May 13, 2008 at 09:51:29PM +0200, David Prieto wrote:
> Hi again,
> > > Ubiquity can now install onto a partition that has an existing home
> > > directory without deleting it. It just removes the system directories.
> Do you have to do anything special for that to work? I usually keep
> my /home in a separate partition, but I have another partition with some
> spare gigs to try Intrepid. This morning I reinstalled Ubuntu in that
> partition and it destroyed the previous /home folder.

I presume that you did not instruct the installer to format the old
/home partition? (If you did, then why?)

If not, then that's a very serious bug. Please report it as soon as
possible with all relevant details, including /var/log/installer/syslog
and /var/log/installer/partman.

> > This is indeed exactly the reason we haven't offered a prominent option
> > of a separate /home; our partition management tools just aren't smooth
> > enough to cope when (not if) people make the wrong choice for relative
> > sizes.
> Actually, the user won't have to make a choice at all. Do you think a
> good choice for an average user could be made automatically depending on
> the disk's size and free space? Because that's what I'm proposing.

No; I don't think such a good choice exists in general, particularly
since when you get it wrong it's so horrifically painful to change. I
also don't actually believe in the mythical "average user" ...

> If you have lots of free space (enough to ensure that it'll be very difficult
> to fill / up, and that /home will be big enough that these few missing gigs
> will be negligible), the installer will recommend you to make a separate
> partition. If space is tighter, it won't.

Unfortunately, the installer has to deal with hard cases as well as easy
cases, and I don't think it's acceptable to just give up with the hard
cases. My bet is that many users won't think it's acceptable either, and
so this will just keep on coming up. I think it's far superior to make
the installer deal with /home in the way that people actually want (at
the high level of "I want to reinstall Ubuntu without destroying my
data", rather than at the detailed level of "which files should go on
which partitions?"), and to do so without having to make fundamentally
painful decisions in the installer that are difficult to change later.

It's very easy to say that a few missing gigabytes will be negligible,
but if those are the few missing gigabytes that prevent Dad from editing
his holiday videos then he'll be justifiably annoyed, particularly if
this was an unnecessary waste of space. Multiple partitions can make
sense on complex installations with dedicated system administrator
capability, but on ordinary desktop installations they are needless
complexity that shouldn't be recommended by default. Unless you have
multiple disks (in which case some of the choices are made for you), the
only reason to bother with them is the (very real) use case of wanting
to preserve your data on installation; I think we should focus on that
use case rather than on the suggested *implementation* of multiple


Colin Watson                                       [cjwatson at ubuntu.com]

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