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Date:      Tue, 9 Jul 2002 20:47:19 -0400 (EDT)
From:      Chuck Robey <chuckr@chuckr.org>
To:        "Brandon D. Valentine" <bandix@geekpunk.net>
Cc:        Matthew Dillon <dillon@apollo.backplane.com>, David Schultz <dschultz@uclink.Berkeley.EDU>, Terry Lambert <tlambert2@mindspring.com>, Erik Trulsson <ertr1013@student.uu.se>, FreeBSD Hackers List <freebsd-hackers@FreeBSD.ORG>
Subject:   Re: swap & huge mem systems
Message-ID:  <20020709204310.N945-100000@april.chuckr.org>
In-Reply-To: <20020709023121.X11678-100000@dallben.homeportal.2wire.net>

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On Tue, 9 Jul 2002, Brandon D. Valentine wrote:

> On Mon, 8 Jul 2002, Matthew Dillon wrote:
>
> >:Thus spake Terry Lambert <tlambert2@mindspring.com>:
> >:> Erik Trulsson wrote:
> >:> > Minimal swap if you want to be able to catch core dumps: Physical RAM
> >:> > size + 64K
> >:
> >:I've caught many core dumps with swap == RAM.  Am I just getting
> >:lucky, or am I losing 64K of the image?
> >:
> >:> Crash dumps good.
> >:
> >:I beg to differ. ;-)
> >
> >    You only need as much as physical ram.  e.g. 1G of ram, 1G on the
> >    dump device (which can be the swap partition).
>
> Allocating swap = physical RAM doesn't buy you any expansion though.  I
> always try to do at least twice physical RAM so that if I ever double
> the RAM in my machine I'm still able to catch crash dumps.  It's not
> worth having to repartition the drive to add more swap every time I add
> more RAM when a 120GB 7.2k drive is ~$170.  What's 2GB of swap on a
> 120GB disk or even a 40GB disk for that matter?

Nope, that no longer computes, Brandon, not when you're using much the
same argument (plus memory's cheap prices) to overpurchase RAM.  I'm
buying a gig of RAM, which is probably 4 times what I really need (even
being liberal about it), so doubling the disk, when future expansion is
already factored in, it makes no sense.

I run a scsi system, where disk is dearer than IDE disks, and that's
another consideration (which I didn't tell you about, I like to win my
arguments unfairly, don't I?)  I just bought that new Fujitsu Ultra160
screamer, fastest disk in the West (3.5ms access, 15K rotation).  Eat my
dust!

>
> Brandon D. Valentine
>

----------------------------------------------------------------------------
Chuck Robey         | Interests include C & Java programming, FreeBSD,
chuckr@chuckr.org   | electronics, communications, and signal processing.

New Year's Resolution:  I will not sphroxify gullible people into looking up
fictitious words in the dictionary.
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