Re: more RAM, swap?

[Petro <petro@bounty.org>]

On Mon, Sep 23, 2002 at 10:58:41AM +0100, Yves Rutschle wrote:
> On Fri, Sep 20, 2002 at 08:24:54PM -0700, Petro wrote:
> [Swap]
> >     Actually, as cheap as disk is these days, I'd leave it alone for the
> >     following reasons: 
> >     (1) It's cheap insurance against a runaway process. 
> How so? If your process is running away, it'll fill your
> swap, be it 16Mb or 1024Gb... You'd actually be better off
> with a smaller swap so the process gets killed earlier on...
> or am I missing something?

    If you've got more swap, you have a longer time to catch it before
    it crashes. 

    Also, some "run away" processes *are* bounded, just with very high
    bounds. 

    Finally, depending on the memory model used, you *may* wind up in a
    spot where the process is using all the memory it can access, but
    the operating system and other applications still have some
    available, I'm not that good with kernel and VM implementations. 

    All in all, you're talking about corner cases, but you're also
    talking about cheap insurance. 

    It really depends on what you use your machine for. I've got a bunch
    of "big" servers, and I want them up as much as possible. If they
    hit swap, they are in *BIG* trouble, going into a death spiral, but
    they still have it available because other things will cause alarms
    to ring, and may, just maybe I can get in and fail over to the
    backup database before things go all Windows(tm) on me. 

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