Subject: Re: Recommended swap (from install notes)
To: Chris G Demetriou <>
From: David Brownlee <>
List: current-users
Date: 08/13/1996 16:12:34
On Sun, 11 Aug 1996, Chris G Demetriou wrote:

> > 	Most of the ports' install notes recommend a swapspace of 2*ram.
> > 	On a 4mb machine this would give <12Mb of virtual memory, which
> > 	seems very tight. Running X+netscape on a 8mb machine with 16mb
> > 	swap also seems optimistic :)
> > 
> > 	Given NetBSD's swap allocation method the 2*ram does not seem
> > 	to apply any more.
> > 
> > 	Would it make more sense to recommend ram+swap figures for
> > 	each of the four options (advise, with X, needed, with X).
> > 	(something of ther order of 32M,64M,16M,32M ?)
> From day one, the swap allocation method has been the same...  Nothing
> new.

	Apologies - my intention was to refer to NetBSD's swap allocation
	method as opposed to the more traditional systems where the 2*ram
	rule was more important.

> It's worth noting that I _do_ think that ~12M of virtual memory is not
> unreasonable for a 4M machine (remember, text pages don't count
> against that).  I've run X on this machine (it has 4M), a few times
> even, and it worked, but you'd have to be a lunatic to want to do it
> often, and you certainly wouldn't want to run netscape.  (just with
> X and 2 xterms: "ooh, i've moved my mouse, not i get to page for 15
> seconds!")
> In other words, I don't think the 2xRAM guideline is unreasonable
> given what one should expect to be doing with a machine with a given
> amount of RAM.  I use that as a guideline, and with the exception of
> heavily-overloaded servers i've never had a problem.
> Almost certainly, if you want to run netscape on a 4M machine, you'll
> need more swap.  However, on a 4M machine, you really don't want to
> run netscape.  8-) 

	I've seen reports of people having trouble compiling large kernels
	& programs on some ports due to the default 'datasize' limit of
	16M. On a 12Mb machine the available virtual memory for a
	compile is probably under 10Mb, (without X running - I know how...
	entertaining... running X in 4mb is :).

	At the other extreme if I had a 64Mb pentium that I wanted to
	put NetBSD onto, but had very limited disk space due to another
	OS already on the disk it would be quite reasonable to allocate
	zero swap.

	swap = 2*ram may be a good rule of thumb, but I think the install
	notes should give recommended mininimum & advised raw+swap values
	as well.

                   David/abs             (

.---- I've been too drunk to love ----.--- I've been too drunk to remember -.
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