Q: Should I have swap?

Daniel Carrera daniel.carrera at zmsl.com
Fri Jun 9 09:32:05 UTC 2006

Jack Wasey wrote:
> Heard you out. You will still benefit from swap. It will improve the 
> performance even when RAM is not maxed out,

It does? I did not know that. Can you explain? Or point to a resource 
that explains this? I'm happy to read documentation to understand this well.

> and as the other posted pointed out, you won't hit a brick wall if it is.

Okay, thanks for the help.

I'd really love to setup RAM quotas or something. It must be possible 
(e.g. each client could get a Linux virtual machine) but it may be too 
much work or it may do more harm than good (e.g. giving each user a LVM 
would mean duplicating Gnome+applications for every user).

> You can tune 
> /proc/sys/vm/swappiness to reduce the tendency to use swap for 
> backgrounding applications, but you're undermining a lot of careful 
> work, research and benchmarking. It's like putting a big spoiler on your 
> car, ruining the millions of pounds of aerodynamics research (and your 
> street cred).

Yeah, I certainly won't fiddle with swappiness. But I would be very 
interested in finding out how swappiness can improve speed even while 
RAM is not maxed out.

"It's like a rainbow. Without an observer at a 23 degree angle to
the light reflected a cloud of spherical droplets, there is no
rainbow. The whole universe is like that. Our spirits stand at a
23 degree to the universe."  -- Zoya Boone, Red Mars

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