Re: super root shell/mode/api

Willy Tarreau
2009-05-20T04:36:20Z

On Mon, May 18, 2009 at 01:12:31PM -0300, Henrique de Moraes Holschuh wrote:
> On Mon, 18 May 2009, Alan Cox wrote:
> > Your distribution failed to configure your system sensibly in that case.
> > Linux has supported a strict overcommit mode for some years, and in that
> > mode a process isn't permitted to drive the system so far out of memory
> > it locks up or hangs.
>
> Err... strict overcommit is vm.overcommit_memory=2, right? That means no
> overcommit at all (as far as the documentation goes, anyway).

exactly

> Which distros enable that by default?

I don't know if mainline distros do this, but some distros dedicated to
embedded systems have been using that for ages, almost since Alan published
his first overcommit patch a long time ago. It's the only way to reach
very long uptimes on servers, as it also protects you against your own
mistakes (eg: stupid actions such as "vi access.log" when the file is
larger than memory).

Willy