[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 18:23:21 CET 2004

Please find my comments in-lined.

Regards / Rolf

Stefan Teleman wrote:
> I think that my earlier rule of thumb recommendation of at least a
> factor of 3 for swap ratio to core RAM falls within the factor of 4
> you quote and use below. And i don't believe your factor of 4 is
> accidental.

Believe me - it is. I explicitly increased it when upgrading
my hard drive. It used to be *32MB*(!)

> And you're not running KDE, but GNOME.

I'd love to try KDE on my machine, but
everybody seems to advide me against
doing that (because of the vast ammount
of memory requirements).

On the other hand they did that about
GNOME too :-) But it turned out it's
not noticable more heavy on resources
than CDE, etc.

> And it's not Solaris 8, but Solaris 7.

Well, my experiences are that new Solaris
releases tend to become more and more "ligiere".

> Have you tried shrinking the swap space on your box to half of what
> it is now ? :-) That would be a factor of 2, and at least a start
> towards proving that you dont' need at least 3 times core RAM.

Actually I've been running Solaris with less that that during
the years. It's only 1 year since I replaced my 1GB (!) disk
with a 36GB one ;-)

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) ;-)

> And here's the first sentence from "Planning for Swap Space":
> "The most important factors in determining swap space size are the
> requirements of the system's software applications."

Stefan, I think you stopped reading that paragraph to early ;-)


"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."


> Nowhere do i  see on that page (or in other subsequent ones) that
> the 3 times rule of thumb is incorrect.

No it doesn't ;-)

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).

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 don't understand your point.
> --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:
>>>based on:
>>>1. experience
>>>2. a tendency of mine to grant more weight to factual, observed
>>>behavior, rather than to one or another particular online article.
>>>3. another tendency of mine to accept the fact that OS's in general
>>>tend to do whatever they want to do, and swap the way they want to
>>>swap, regardless of what people think or hope they _should_ be doing.
>>>4. when faced with a fairly trivial problem which has three possible
>>>      a) shrink KDE
>>>      b) rewrite the SunOS swapper
>>>      c) increase swap
>>>i try to choose the most practical and easily implemented solution (c).
>>>Rolf Sponsel wrote:
>>>>What do you base that "rule of thumb" on?
>>>>This sounds to me, like an old SunOS myth, and
>>>>is not in accordance with, e.g. this article.
>>>>Best Regards / Rolf
>>>>Stefan Teleman wrote:
>>>>>The rule of thumb for determining the minimal amount of swap space is:
>>>>>at least 3 times core RAM.
>>>>>That means, for a workstation with 640MB core RAM you need _AT LEAST_
>>>>>1920MB swap. which you can probably safely round up to 2048MB.
>>>>>Running out of swap on 640MB core with 1GB swap is not surprising at
>>>>>On Monday, January 26, 2004, Michael Szengel wrote:
>>>>>[ ... snip ... ]
>>>>>>For your reference:  my Sun Blade 100 has 640 MB RAM and had 1 GB swap. I
>>>>>>had to extend the swap by 500 MB in order to survive the days without the
>>>>>>error message you mentioned.
>>>>Rolf Sponsel
>>Rolf Sponsel


Rolf Sponsel


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