[kde-solaris] swap space requirements [was: KDE 3.1.4 - Can't talk to klauncher]

Rolf Sponsel Rolf.Sponsel at kstr.lth.se
Mon Jan 26 22:30:40 CET 2004

Stefan Teleman wrote:
> Rolf Sponsel wrote:
>>Tell me; do you really think that I'll *have to* add another 0.5 GB
>>swap space to my system when - if - I decide to add another 128MB?
>>I do not - rather on the contrary (should I want reduce it) ;-)
> Great! Please, reduce it.

No, I won't wast any time on doing that.

But I will try and see what happens when
I add another 128MB to my system, without
increasing the swap space. ;-)

> My only request is: please post your
> /var/adm/messages after you do so. :-) If you can still use vi,
> that is.

I'd be very, very surprised if I could not (probably
will be able to use emacs in vi emulation mode too ;-)).

> Yes, you do need to increase swap whenver you increase core RAM.
> Especially for workstations which come with a small amount of core
> RAM to begin with. Whether it should be done at 128MB or 256MB,
> that's a matter of tolerance. But, 128MB RAM is significant enough
> to warrant increasing swap, especially when you had very little swap
> to begin with.
>>"The most important factors in determining swap space size are the
>>      requirements of the system's software applications. For example,
>>large applications such as computer-aided-design simulators,
>>database-management products, transaction monitors, and geologic
>>analysis systems can consume as much as 200-1000 Mbytes of swap space."
>>But, these large applications, I suppose, are to run in a desktop
>>environment *and* none of the examples given in the general
>>guidelines have swap space that is larger that the pysical memory
>>(they're actually 1/4:th of the size of the physical memory).
> Actually, database servers or geologic analysis systems usually run
> on enterprise-class multiprocessor servers, not on desktops. The GUI
> may run on desktops, but the engine runs on servers.
> ... DELETED ...

Yes you are right - huge database servers do mostly run on
desktopless systems. I've probably worked to long with CAD-
/CAM systems and therefor those where the first that came
to my mind (and they often run on a desktop system), and
would correspond to the first example in the general guide-
lines, i.e. a "Workstation with approximately 4 Gbytes of
plysical memory" should need about "1Gbyte swap space".

>>I really doubt that KDE should require 4 times the size of the
>>physical memory to run. If so!? It must be really, really badly
>>broken (hopefully not by design).

> I never said KDE required 4 times core RAM. What i said was:
> the rule of thumb for sizing swap is at least 3 times core RAM.

Which finally brings us back to my initial question where I
claimed that:

"This sounds to me, like an old SunOS myth, and
  is not in accordance with, e.g. this article."

And that's why I posted the link to the article;


I wanted to know whether the myth is true, *or*
if the myth is a myth. (This said in response to
André Schneider's response - There is no problem ;-) )

I know this was true in the old good days when running
SunOS 4, where the physical memory required to be backed-up
by "disk-backed" swap space (which also seems to be true
for the majority of other non-Solaris Unix systems), and
therefore might hang around as a "rule of thumb".

And as I wrote initially:

"I really don't want to argue with you ..." :-)

Regards / Rolf

> ... DELETED ...
> --Stefan
> -----
>>>Rolf Sponsel wrote:
>>>>Best Stefan,
>>>>I really don't want to argue with you, but
>>>>your experiences are different to mine, and
>>>>I cannot find any support for your "rule of
>>>>thumbs" in the Solaris documentation either. :-(
>>>>docs.sun.com: System Administration Guide: Basic Administration
>>>>Have a look under the title "Planning for Swap Space".
>>>>Best Regards / Rolf
>>>>BTW, I'm running GNOME 2.2 on Solaris 7
>>>>     on a SPARCstation 5 with 128 MB and
>>>>     512 MB Disk Swap quite acceptable.
>>>>   ( the factor 4 here :-) accidentally
>>>>     corresponds to what you recommend
>>>>     mainly because I need that much when
>>>>     compiling H323 software ). -Not bad.
>>>>Stefan Teleman wrote:
>>>>> ... DELETED ...


Rolf Sponsel


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