Swap space question

[Aaron Konstam]

On Sat, 2006-09-30 at 16:19 +0300, nicolas angel wrote:
> Hi,  i would to ask something about swap space:
> 
>  i quote from the book "How Linux Works—What Every Super-User Should
> Know"
> 
> "Reserve two to five times as much disk space as you have real memory
> for swap. It doesn't make sense to go any lower, because you may
> actually risk running out of memory. If you go higher and actually
> intend to use all of this swap space, you will likely suffer serious
> performance problems because the system will spend all of its time
> swapping (a condition known as thrashing). " 
> 
> i can't understand why if create a really big swap partition i will
> have a performance decrease????It seems to me
>  that in the worst case scenario, i will be throwing disk space
> [because the system will never use the swap partition if it doesn't
> need it......why this would have a negative impact on the
> system......] 
> 
> thanks in advance,
> 
> Nicolas Ang
> -- 
This is an argument you can get into in any Linux bar. In modern Linux
having more than 2 x RAM as swap is a waste of disk space. Ans even that
much is probably to big for most users. 

I have doubts that most people know how swap is used by the kernel and
why there is a swap area. People think it is a primary part of the
virtual memory system used by the system. Well the virtual memory system
and swap are two different things and used at different times for
different  purposes. There is at least one book on the Linux 2.6 kernel
that explains all this.

I really don't want to hear from all those who will tell me they
understand all this. All I want to say is you seem not to and if you are
interested you can read up about it.
-- 
Aaron Konstam <akonstam at sbcglobal.net>