Re: Overcommitable memory??

From: James Sutherland (
Date: Wed Mar 15 2000 - 17:30:06 EST

On 15 Mar 2000, Rask Ingemann Lambertsen wrote:

> Den 13-Mar-00 15:01:14 skrev Richard B. Johnson følgende om "Re: Overcommitable memory?? Re: Some questions about linux kernel.":
> > Of course, if you don't have a swap-file, there is nothing you can
> > do. Some persons claim that a swap-file isn't necessary and should not
> > be used. They come from the "Flat Earth Society".
> Swap isn't necessary. Swap is just a cheap and slow alternative to RAM
> chips, that's why most people use it, hoping mostly inactive parts of
> memory have to be implemented as swap, but swap isn't necessary. It is
> quite possible to run production Linux systems without any swap. Been
> there, done that.

True, it isn't ESSENTIAL to have swap. Having swap space does, however,
enable more efficient usage of your physical RAM (little-used data can be
paged out, saving physical RAM without any performance degradation.) It
also gives a very cheap safety marging against OOM problems - rather than
getting hard failures as soon as physical RAM is exhausted, you get
(recoverable) disk thrashing, and can still log in to fix things.

So you're right, swap is not essential - just very useful in most


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