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

[Przemek Klosowski]

On 04/13/2015 11:34 PM, Zbigniew Jędrzejewski-Szmek wrote:
> 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.
Exactly! remember that a typical disk speed is few tens of MB/s, i.e. 
about 1 GB/min. I came to the conclusion that anything more than 4GB is 
just counterproductive. Large swap just deceives us into thinking that 
we can run jobs larger than the physical memory but that is really not 
the case, just like Seymour Cray said [1].

Maybe swap space should simply be max(4GB, $PhysicalMemory). Actually, 
isn't 'swap to filesystem' still an option? if so,  maybe swap should be 
a constant 4GB, and hibernation should create an appropriately sized 
file on the fly, join it to the swap and use both.
> 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.
Absolutely agree.

[1] http://hackersays.com/68b2b7
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