lubuntu-qa team mailing list archive

[Phill Whiteside <PhillW@xxxxxxxxxx>]

Hi,

a very simplistic background... Ubiquity, the desk top installer, needs
more RAM to run the install than lubuntu itself needs to run. To allow
people to use the DE installer, lubuntu runs a specific job to enable zram
before the swap partition is actually created. Prior to that, the only way
was for such low RAM systems to pre-prepare a swap partition. Creating a
swap partition is not for new comers!

For people with really low ram, we do suggest using the minimal install
https://help.ubuntu.com/community/Lubuntu/Documentation/MinimalInstall and
use of
https://help.ubuntu.com/community/Lubuntu/Documentation/MinimalInstall#Low_Resource_Browser

 These specific cases are covered in our wiki, but do need a bit of 'geek'
in the person who wishes to use them. Using zram in the installer allows
lubuntu to work with the "hold your hands" Ubiquity installer on lower spec
RAM machines than was previously possible. This is an important step for
the XP users who have no experience of installing a new system and need the
installer to "hold their hands" during what will be quite a scary
experience for these orphans.

It is precisely because of low resource machines that lubuntu is the only
flavour who maintains an alternate version which is based on the server
installer. This does massively increase the number of ISO's we need to test
(by a factor of two). :)

Please do realise that this is how things are according to my limited
knowledge; I'm sure others can fill in the more technical details.


Regards,

Phill.




On 11 October 2013 19:08, JM <meets@xxxxxx> wrote:

> Hello Nio,
>
> On Fri, 11 Oct 2013 14:01:39 +0200
> Nio Wiklund <nio.wiklund@xxxxxxxxx> wrote:
>
> > > Hi,
> > >
> > > I would have liked to read from your tests if the machine slows down
> by swapping too
> > > early while some memory is still available or if it uses most of the
> physical RAM
> > > before doing so. You could see it by having htop running in a console
> and keep on eye
> > > on proc and ram use at the top of the console while starting and using
> applications.
> >
> > I *was* watching the memory usage and process activity with htop :-)
>
> Ok. :)
>
>
> > It was swapping before the memory was fully used (Lubuntu is always
> > doing that, with or without zRAM). I have not changed the swappiness
> > from the default value.
>
> I have found the same so far. During install time the install can even be
> slower and
> slower while the use of the swap disk is increasing.
>
>
> > > I have done tests with ZRAM, in an iso I am doing (a personal remix
> done with
> > > ubuntu-builder) and have not finished yet. It consists in once having
> the
> > > configuration default provided by the zram-config package, then in
> another ISO switch
> > > to the configuration I have described before.
> > >
> > > I still have one test to do which could make a difference.
> > >
> > > Linux kernels have been known to swap to disk too early since many
> years, and the
> > > following configuration is a mean to limit the too early swappiness.
> >
> > I think some (or many) people want it that way, to have a margin, when a
> > large chunk of RAM is needed, and I have followed discussion threads
> > about swappiness. Some people claim there should be different settings
> > for servers compared to desktops & laptops (more swappiness for
> > servers). I have not tested with different swappiness, so I have no own
> > experience.
>
> I have not studied/tested anything related to servers, I can't talk about
> that. I can say
> with a Live desktop while installing the use of the swap disk increased up
> to almost 30%
> of the available ram, while lots of ram was still available.
>
> (I'll show pics later when I will have found the time to perform the last
> tests).
>
>
> > > So the test I want to do at last will consist in using the default
> zram-config
> > > configuration and add just this:
> > >
> > >
> > > **********
> > > vm.swappiness=0
> > > vm.vfs_cache_pressure=50
> > >
> > > # Uncomment the next line if we are running a laptop
> > > # vm.laptop_mode = 1
> > >
> > > **********
> > >
> > > as a file such as 50-local.conf in /etc/sysctl.d.
> > >
> > > I wanted to try in Lubuntu but ubuntu-builder has not been able to
> redo a bootable ISO
> > > from from the build directory after I added the file in the Lubuntu
> filesystem and
> > > generated a new ISO.
> >
> > I can try it in an installed system. It is easier and also more
> > interesting for me :-P
>
> Ok, I'll try to do what I suggested with a live USB and persistent mode
> because I would
> like to see how the behavior is while using Ubiquity to install to hard
> drive.
>
>
> > -o-
> >
> > I think the ramdisk makes it harder for the memory management in the
> > live system,
>
> Sorry I didn't understand this part: did you mean "ramzswap" or did you
> mean "swap to
> disk"/swap partition ?
>
> > which could explain why it choked earlier than the
> > installed system with 256 MB RAM.
>
> I think 256 MB RAM is too little for any modern system. Even the Ubuntu
> Openbox Remix I
> work on, which has a few components less does not behave in a very snappy
> way on a
> machine with so little RAM, and let's not forget what the GPU can bring or
> remove, when
> it works with shared memory.
>
> Regards,
> Mélodie
>
>
> --
> Mailing list: https://launchpad.net/~lubuntu-qa
> Post to     : lubuntu-qa@xxxxxxxxxxxxxxxxxxx
> Unsubscribe : https://launchpad.net/~lubuntu-qa
> More help   : https://help.launchpad.net/ListHelp
>



-- 
https://wiki.ubuntu.com/phillw