Re: 2.4 and 2GB swap partition limit

David Lang
2001-04-28T19:30:36Z

at the low end useing a bit of disk for swap doesn't hurt, I ran into a
case a couple years ago on AIX systems. we buy them with 2G ram so that we
don't need to swap, but discovered (the hard way) that we also needed to
allocate 4G of disk space for those boxes (allocating less then 2G meant
that we couldn't use the 2G of RAM). This meant that we had to go out and
buy 2nd hard drives for every machine, just to put the swap files on.

now disks are larger today so it's not as much of an issue, but even with
modern 9-18G drives you can end up eating up 20% or more on a large
machine, this starts to be significant. you can try to say that any box
with that much ram must have lots of disk as well, and most of the time
you will be right, but not all the time. there are cases (webservers for
example) where the machines will be built with lots of RAM and CPU and
little disk becouse they get all their content and put all their logs
elsewhere on the network. in fact with the advances in flash size and the
desire to create high performance clusters, I would not be surprised to
see web node machines produced with no hard drives. it means one less
thing that can break on the system (think a rack of transmeta powered
boxes with no moving parts in the rack except possibly fans)

David Lang

On
Sat, 28 Apr 2001 R.E.Wolff@BitWizard.nl wrote:

> Date: Sat, 28 Apr 2001 16:11:47 +0200 (MEST)
> From: R.E.Wolff@BitWizard.nl
> To: Wakko Warner <wakko@animx.eu.org>
> Cc: Rogier Wolff <R.E.Wolff@BitWizard.nl>,
> Xavier Bestel <xavier.bestel@free.fr>,
> Goswin Brederlow <goswin.brederlow@student.uni-tuebingen.de>,
> William T Wilson <fluffy@snurgle.org>, Matt_Domsch@Dell.com,
> linux-kernel@vger.kernel.org
> Subject: Re: 2.4 and 2GB swap partition limit
>
> Wakko Warner wrote:
> > > So you've spent almost $200 for RAM, and refuse to spend $4 for 1Gb of
> > > swap space. Fine with me.
>
> > I put this much ram into the system to keep from having swap. I
> > still say swap=2x ram is a stupid idea. I fail to see the logic in
> > that. Disk is much much slower than ram and if you're writing all
> > ram to disk that's also slow.
>
> > I have a machine with 256mb of ram and no disk. It runs just fine
> > w/o swap. Only reason I even had swap here is if I ran something
> > that used up all my memory and it has happened.
>
> > Since when has linux started to be like windows "our way or no way"?
>
> I've ALWAYS said that it's a rule-of-thumb. This means that if you
> have a good argument to do it differently, you should surely do so!
>
> I maintain a 32M machine without swap. My workstation has 768Mb RAM
> and almost 2G swap:
>
> /home/wolff> free
> total used free shared buffers cached
> Mem: 770872 766724 4148 0 259816 78308
> -/+ buffers/cache: 428600 342272
> Swap: 1843212 1840 1841372
> /home/wolff>
>
> That disk space is just sitting there. Never to be used. I spent $400
> on the RAM, and I'm now reserving about $8 worth of disk space for
> swap. I think that the $8 is well worth it. It keeps my machine
> functional a while longer should something go haywire... As I said:
> If you don't want to see it that way: Fine with me.
>
> Roger.
>
>
>
> --
> ** R.E.Wolff@BitWizard.nl ** http://www.BitWizard.nl/ ** +31-15-2137555 **
> *-- BitWizard writes Linux device drivers for any device you may have! --*
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