[gentoo-user] Re: To swap or not to swap? Is it really needed?

[Nikos Chantziaras <realnc@arcor.de>]

On 12/30/2011 12:34 AM, Claudio Roberto França Pereira wrote:
> Anyway, for the last days, my machine has been really slow, with mouse
> lag, input delay, and other things. I imediately associated it to the
> lack of free RAM, but I always rushed to check the RAM usage with htop
> and it were never really high. So today I decided to turn my swap
> partition off. And the system is FLYING. I mean, it's pratically a new
> machine, now it's usable and reliable.
> [...]

Usable, yes. Reliable, no ;-)  Once RAM runs out, random processes get 
killed.  Possible data loss due to that.


> So, should I ban swap partitions entirely from my life? Is that ok?

No.  You simply tweak swappiness.  In your /etc/sysctl.conf, add this:

   vm.swappiness = 20

The default value is 60.  Which makes the system use swap very early on. 
  With 20, you pretty much will swap only when really needed.  I've read 
somewhere that values lower than 20 are not recommended, but I don't 
remember where or why.