Hello,
(I have deleted some parts of your mail because I should answer only
"yes" "ok" or "I agree")
On Jan/20/2005, Les Bell wrote:
>
> Carles Pina i Estany <[EMAIL PROTECTED]> wrote:
>
> >>
> Everything about this topic is a opinion, but not some rules in some
> "old" Kernels (2.0 or 2.2, I remember that i have read some problems
> with less swap than RAM memory for some algorithms). But not today!
> <<
>
> I think that pretty much sums it up - you can produce good rules only by
> taking into account:
>
> * The kernel version (does it have the OOM Killer patch)
> * The application working set in-memory and total requirements
> * The hardware configuration (large or small hard drive, or no hard drive
> at all, e.g. embedded system)
Ok, I agree 100% with this: we can have some rules if we have "all"
information...
> >>
> good point to have more swap space to feel that something is not going
> fine, I like the idea.
> <<
>
> I think it's a reasonable scheme for single-user (e.g. desktop workstation)
> systems. The best approach is to stay well away from unexpected (to the
> user) effects, whether it be processes being suddenly killed or the system
> freezing. A sluggish system with the drive activity light constantly
> flashing usually is enough to convince the user to back off before any
> "damage" is done. Of course, this can't work for multi-user systems, e.g.
> servers.
yes, I think that your article was talking about desktop computers,
and I was thinking for "all computers" (desktop and servers).
For desktop computers it is fine to have "a lot of swap" so user can
feel something is going bad.
But, maybe, an applet that says "You need more RAM" is the same to
convince user to "do something" like hard disk LED. Well, yes, with hard
disk the system will be slow (better to convince a user than only a
applet saying something)
Always thinking that some minimal swap is recommended.
> >>
> Althouth, sometimes Linux uses swap space only to safe RAM from some
> sleeping (for long time) processes. So maybe we have a big process into
> the swap (so, free will say that we are using swap) and the system is
> really fast: everything that we are using is in RAM.
> <<
>
> That's true, but I think that will be an unusual situation for the most
> common workstation and server environments, since those processes are
> things that usually load and initially run during system startup, so they
> usually fit quite easily in RAM and don't represent much space in the swap
> partition. If the swap partition is 3x RAM, and is being used heavily, it's
> almost certainly by runnable processes. I should probably add </opinion>
> here. ;)
I can add other opinion, that it is if you really need 3X swap, your
sytem will be veeery slow and you should buy more RAM :-) (yes, there
are some cases that you will need a lot of swap and it is not needed to
buy more RAM, for example mastering a Knoppix CD, etc. etc.)
> >>
> Thank you for your answer, and excuse me some differing opinions...
> maybe I don't know something or something that I know it is not in good
> way.
> <<
>
> Thank *you* for raising it - you've made me revisit the topic and I'm going
> to add some more detail to my course materials. I think the picture that's
> emerging is that the topic is *not* a simple one, and that simple questions
> in the tests may not be appropriate. Hopefully others will have more to add
> - and we haven't even considered things like suspend-to-swap yet. . .
exactly, I have thought about this but I haven't said anything,
suspend-to-swap maybe is not very usual (at least at the moment)...
but we should think about this when we make partitions.
I don't know if there are some swap questions like "how to parallelize
swap partitions", maybe are interesting questions too.
Just for curiosity, the swap area in LPI is maintained by Mark Miller,
Mark is subscribed on this list to know about our "discussion" and
will think about this? We should send to him our "discussion"?
--
Carles Pina i Estany GPG id: 0x8CBDAE64
http://pinux.info
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