lubuntu-qa team mailing list archive

[Nio Wiklund <nio.wiklund@xxxxxxxxx>]

On 2013-09-28 12:28, Joyce MARKOLL wrote:
...
> 
> Hi,
> 
> I have said what follows in other posts on this list lately, however I will repeat it:
> 
> I have used zram in Ubuntu 12 as well as in the present Lubuntu Saucy testing and I don't
> meet with any freeze : I suspect your kernel(s) want to swap to disk which does cause
> freezes.
> 
> Last year I installed antiX (based on Debian testing) on a very very old machine, HP
> Omnibus with 192 MB ram and a 800 Mhz celeron processor : I had to configure the
> swappiness to prevent the kernel from swapping to disk. Once done the zram module (and
> the associated scripts) did a very good job.
> 
> Could you try where your distributions do "freeze" to ask the kernel to not swap to disk?
> Here is a configuration file:
> http://meets.free.fr/Downloads/BentoVillageProject/Configurations/System/etc/sysctl.d/50-local.conf
> 
> of course, it is meant to be added to /etc/sysctl.d
> 
> Else, I configure 20% or 25% max in the initramfs.conf file (under /etc/initramfs-tools)
> ie: COMPCACHE_SIZE="20%"
> 
> (I have explained in another thread that 50%, which is the default in Ubuntu for a reason
> which is unknown to me, might take too much from the CPU... and the above configuration
> is what I have been using in several distributions since several years with success, as
> well as a few dozens of users whom I provided with remixes having this setup).
> 
> Let me also add a word about the swap to disk : it is highly desirable to avoid swapping
> to disk, because it is very slow compared to swap to ram and therefore likely to trigger
> freezes.
> 
> You can find more information about zram here:
> http://code.google.com/p/compcache/w/list
> 
> Regards,
> Mélodie
> 
> 

Hi Mélodie,

Do I understand correctly, you say that zRAM and swap to disk cannot
cooperate, and therefore freeze the system? That sounds like a bug to
me, and a bug-fix should solve that problem, because I think some people
want both.

Otherwise, what happens, when the system is running out of memory? I
agree, swap to disk is very slow, but what is the alternative if you
want to hibernate the system instead of shutting down? (I prefer
shutting down, but I know that some people hibernate their computers.)

Would it be worth trying to run the system you care about (for example
Raring or the Saucy current daily build) with zRAM on but swap to disk
off, and try to provoke it to freeze?

Best regards
Nio