Bug#652275: Guided partitioning should not offer separate /usr, /var, and /tmp partitions; leave that to manual partitioning

[Josh Triplett <josh@joshtriplett.org>]

On Sat, Dec 17, 2011 at 05:42:59PM +0800, Thomas Goirand wrote:
> On 12/17/2011 05:12 AM, Josh Triplett wrote:
> > And while we might
> > debate the usefulness of a separate /usr back and forth, I think I can
> > safely say that it won't become a *recommended* configuration anytime
> > soon. :)
> 
> I do recommend a separate /usr to anyone. It's *not* safe to say that,
> and I know many people that agree with me. To me, it has, and still is,
> the best choice. You have no rights to arbitrary decide what should
> be/was/will be the recommended configuration. Your choice is not more
> valid than mine, and (computer) science isn't about majorities anyway.

Let me clarify: I can safely say it won't become *Debian's* recommended
configuration anytime soon.  It has strong enough arguments against it
that while a vocal minority might manage to keep it around, I doubt
it will become the default.  The discussion would have to change quite
drastically for that to occur.

> On 12/17/2011 05:12 AM, Josh Triplett wrote:
> > For the installer, "easy" represents a significant component of
> > "do the job and do it well".
> > Sure; see below for a more detailed suggestion along these lines.
> > However, I also don't think that should stop us from optimizing
> > for the common case.
> 
> Well, commonly, for a desktop computer, I recommend separated /usr,
> /var, /tmp and /home. Reasonably, if you put enough space for it (for
> example, 16GB for usr, 8GB for var, 1GB for tmp) then you can set the
> rest for /home. Today's HDD are really big, and in most cases, this
> setup will work very well for a desktop, and you'll be able to install a
> really insane amount of software without filling up /usr or /var. If you
> then lack space, LVM is there.

Brand new laptops, *today*, come with as little as 300GB drives, or 80GB
SSDs.  Netbooks often have even less than that.  Wasting ~20GB of that
seems excessive.

And do you seriously expect the average user to go through the process
of an LVM resize?  "Possible" doesn't mean "easy".

> Doing this has many advantage. Like, if your laptop has to unexpectedly
> reboot (like when you inadvertently removed power cord when batteries
> were not plugged, which happens often in real life), having separated
> partitions usually makes the fsck faster. Only some of the partitions
> may have dirty bits to clean, and there's a very good chance your /usr
> (which holds a lot of files and is long to check) doesn't even need a
> check. That alone is a cool feature that justifies having a separate
> /usr for me.

Modern fsck runs very fast (in large part by not checking unused bits of
the filesystem).  Also, unless you've mounted some of those partitions
read-only, they'll all always need fsck when not cleanly shut down.

> When it comes to *real* newbies (here, I'm thinking about people like my
> father in law or my wife who really, don't want to know what is
> partitionning), they wont go to hit corner cases and fill any of the
> partitions of their HDD anyway. For them, I see no issue "wasting" a bit
> of space on multiple hundreds of GB space that will anyway never be used.

On the contrary, significant overlap exists between the set of users who
don't want to think about advanced concepts like partitioning and the
set of users quite capable of filling a disk and installing piles of
software.  If you really don't want to know about partitioning, you
don't want to deal with situations where you have plenty of free space
but not on the partitions where you need it.

> > Only in the case where you have such a big disk that you can afford to
> > waste a pile of space with mostly empty partitions. Personally [...]
> 
> In most general cases nowadays, we *do* have huge disks. Just have a
> look into what's available in the marketplace. If you lack space in one
> of the default partitions, you can resize using LVM anyway.

See above; we don't have sufficiently huge disks to waste enough space
that the non-/home partitions will never fill up, and we don't want to
inflict partition resizes on most users unnecessarily.

- Josh Triplett