[clug] to swap or not to swap that is the question

[Kim Holburn]

Yeah thanks Sam, that sounds right and basically answers my questions.

Kim
On 2004 Jun 29, , at 10:24 PM, Sam Couter wrote:

> Kim Holburn <kim.holburn at anu.edu.au> wrote:
>> I have read several places that linux systems are always better with
>> (HD) swap (suggestions were that swap allows the system to not run out
>> of memory).  I don't understand this.
>
> I think these opinions may be outdated, and come from the days when a
> machine with 64Mb RAM was considered a supercomputer.
>
> Running out of memory (including swap) is BAD BAD BAD. It causes much
> non-deterministic behaviour for many reasons. Lots of programs and
> libraries don't deal with malloc() failing, so programs crash. Linux
> will overcommit memory by default, so even if malloc() succeeds, when
> you try to address the memory it may not physically exist. Linux also
> has an OOM killer which will pick the largest running program and
> unceremoniously kill it. So Bad Shit (tm) will happen.
>
> Having said all that, I believe running out of virtual memory is the
> same thing whether that memory is all chip (RAM) or whether some of it
> is hard drive. This may not have always been the case, however.
> -- 
> Sam "Eddie" Couter  |  mailto:sam at couter.dropbear.id.au
> Debian Developer    |  mailto:eddie at debian.org
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-- 
Kim Holburn
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National Information and Communication Technology Australia
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