lubuntu-qa team mailing list archive

[Phill Whiteside <PhillW@xxxxxxxxxx>]

Hi,

there is much mis understanding about swap. Every one *seems* to think it
is only used when physical RAM is exhausted. it is *NOT*. Linux will use
swap to 'swap out' areas that are not being actively used according to
their "swappiness" I give you one simple example from my server.....

Mem:  16238108k total, 15933004k used,   305104k free,   292976k buffers
Swap: 11011664k total,  3902064k used,  7109600k free,  3843884k cached

16GB of RAM, and it shows 15.9 GB used.... Then look at what is cached,
3,8GB this is the area for stuff that is in 'fast swap' i.e. RAM So, why is
the machine using 3.9 GB of hard disk swap? Simply because the kernel has
decided that all that area is not needed too often. The fact the two
figures are similar means nothing, it is co-incidence for the time snap of
my server.

Here is piglet..

KiB Mem:   3787680 total,  3626104 used,   161576 free,   177248 buffers
KiB Swap: 10166660 total,    13492 used, 10153168 free,   926720 cached

~ 1 GB out of 4GB is in cache, then add in the buffers... Yet even my
humble laptops' linux kernel has decided that there is stuff about that can
be 'relegated' to hard drive.

As always, if you look into the wiki area, the answer is there... Here's an
easy link to it
http://askubuntu.com/questions/157793/why-is-swap-being-used-even-though-i-have-plenty-of-free-ram

As to the entire functioning of z-RAM and how it interacts with the kernel
to decide what goes where, you'd have to read the z-RAM pages.

Regards,

Phill.

On 19 July 2013 12:04, Ali Linx (amjjawad) <amjjawad@xxxxxxxxx> wrote:

> On Fri, Jul 19, 2013 at 1:44 PM, Phill Whiteside <PhillW@xxxxxxxxxx>wrote:
>
>>
>> Rule #1: Always expect the user to do something you had not planned
>> for....
>> Rule #2: Read Rule #1..
>>
>> Regards,
>>
>> Phill.
>>
>
> +1
> Totally agree. Better Safe Than Sorry ;)
>
> Hmm, now, I'm thinking how can I fill my 4GB RAM on Core i5 machine using
> Linux ... this is going to be fun :D
>
> --
> *Remember: "All of us are smarter than any one of us."
> *Best Regards,
> amjjawad <https://wiki.ubuntu.com/amjjawad> - StartUbuntu Project<https://wiki.ubuntu.com/Lubuntu/CommunicationsTeam/WOWLubuntu/StartUbuntu>
>  - Linux Brainstorming <https://www.facebook.com/groups/352004991569676/> -
> Mubuntu<http://amjjawad.blogspot.com/2013/07/draft-mubuntu-simple-minimal-system.html>
> Peppermint <http://peppermintos.com/about/> - Ubuntu GNOME<http://ubuntugnome.org/>-
> Xubuntu <http://xubuntu.org/>
>
>
>


-- 
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