Importance of LVM (was Re: Partitioning criteria revision proposal)

[Adam Williamson]

On Thu, 2012-10-25 at 20:14 -0600, Chris Murphy wrote:
> On Oct 25, 2012, at 7:38 PM, Adam Williamson <awilliam at redhat.com> wrote:
> > 
> > Nothing gets 'wedged in' anywhere, there is no code to 'put in' (nor
> > will any of the code that exists get 'removed' even when we default to
> > btrfs, I don't think).
> > 
> > I already posted the patch: it's two lines. All the code for LVM
> > autopart already exists and is the same code that has existed for years.
> > The patch simply changes the way the autopart code is called from
> > 'please don't use LVM' to 'please use LVM'. It is two lines.
> > http://fpaste.org/w1vE/
> 
> So the loose proposal here is to add this patch just for F18, and then undo it for F19?

The general understanding among Storage People is that we're aiming to
go to btrfs by default for F19. Finally. That's one of the arguments
against changing the default _now_, for one release (or possibly two),
only to change it again shortly.

> 
> > 
> >> I like LVM. But I don't care about LVM as default for autopart one way
> >> or another. We're just post beta freeze, and this is coming up for
> >> serious conversation now? I think it needs to be let go. I think Jesse
> >> Keating's reply is a sufficiently good and timely explanation for
> >> having set expectations well prior to now.
> > 
> > The tricky thing is that the argument kind of cuts both ways: the thing
> > that's the big change here was changing from LVM-by-default to
> > raw-ext4-by-default, and that should have been clearly publicised and
> > discussed. The fact that there are people just now finding out that it
> > happened and being unhappy about it rather indicates that the planned
> > change _wasn't_ properly communicated.
> 
> There are other explanations than it being improperly communicated.
> 
> We've had this same autopartitioning behavior for how many weeks? It
> is only affecting autopartitioning. I'm not realy clear what the
> downside even is, which is why I didn't have a fit over this two
> months ago. It's just a default for most people who either don't care,
> or don't understand the alternatives. Everyone else will use Manual
> Partitioning.
> 
> I think the public beta will make this more clear, however, how many
> people really expect LVM autopartitioning. But I really don't think
> it's that big of a deal. It's a default. Don't like the default?
> Change it.

You're probably right if everyone takes a step back that it's not a
_huge_ deal. It's slightly more difficult to change in newUI than it was
in oldUI, as things stand: there's no drop-down/checkbox 'change the
autopart algorithm' thing as there was in oldUI. You have to go into
custom partitioning and either create an LVM-based layout from scratch,
or hit 'create partitions automatically' and then change their type to
LVM. But it's not a huge problem, no, and you'd think people who are
LVM-savvy could handle it.

If anything the debate is about the experience of those who don't really
care at install time, but theoretically might later. Some worry about
the 'difficulty' of understanding LVM for these non-caring users. Some
suggest that maybe these non-caring users might hit a problem they can
solve with the help of LVM, like filling up their / partitions. As
always with Fedora debates it's a bit fuzzy because we don't have any
good data. Plus ca change.
-- 
Adam Williamson
Fedora QA Community Monkey
IRC: adamw | Twitter: AdamW_Fedora | identi.ca: adamwfedora
http://www.happyassassin.net