hibernation support - lack of distro-wide coordination between systemd, dracut, anaconda, pm-utils and maybe more?

[Zbigniew Jędrzejewski-Szmek]

On Mon, Apr 13, 2015 at 07:20:46PM -0700, Adam Williamson wrote:
> On Tue, 2015-04-14 at 00:39 +0000, Zbigniew Jędrzejewski-Szmek wrote:
> > On Mon, Apr 13, 2015 at 04:39:38PM -0600, Chris Murphy wrote:
> > > OK not everyone is on the same page, apparently. This bug was just
> > > closed by Anaconda as WONTFIX.
> > > 
> > > suggested swap for laptop seems low
> > > https://bugzilla.redhat.com/show_bug.cgi?id=1037472
> > > 
> > > I don't see how hibernation works reliably with such a low default 
> > > swap size.
> > Yeah, hibernation is automatically invoked when battery runs low 
> > (and is generally
> > useful in other cases), so we should provide enough swap for it to 
> > work. With
> > moern disk sizes 4GB one way or the other is hardly noticable,
> 
> 'Modern disk sizes' like the 128GB (that's GB, not GiB) that's 
> standard on the basic XPS 13 developer edition model, fr'instance? 
> http://www.dell.com/us/business/p/xps-13-linux/pd
That one's tough. Disk is less than 15 times memory size (30 or 60 for
the higher end models).

OK, so swap 2x memory seems excessive. Actually swap with the same as
memory should work *most* of the time. There's no guarantee that any
amount swap will be enough, since it could all be filled by the time
hibernation is requested, but we should try to cover most normal
usage. But considering that swap will be slow on HDD, so users will
most likely avoid using more than a small amount, and SDD are small,
so it's expensive to provide bigger swap, the default that anaconda
uses seems OK. An exception is for computers with small amount of RAM
(<= 2GB?). There swaps is more likely to be filled and the default
size for swap should imho be higher than the amount of RAM.

The details can be worked out. But I don't understand the justification
for closing of the bug:

(In reply to David Lehman from comment #1)
> Anaconda does not automatically configure systems for hibernation at this
> time.
Hibernation is important for many use cases, including graphical
environments, and anaconda should support them.


Zbyszek