From owner-freebsd-questions Wed Dec 26 11:17:44 2001 Delivered-To: freebsd-questions@freebsd.org Received: from elvis.mu.org (elvis.mu.org [216.33.66.196]) by hub.freebsd.org (Postfix) with ESMTP id 128E337B405; Wed, 26 Dec 2001 11:17:33 -0800 (PST) Received: by elvis.mu.org (Postfix, from userid 1192) id 8991481D01; Wed, 26 Dec 2001 13:17:27 -0600 (CST) Date: Wed, 26 Dec 2001 13:17:27 -0600 From: Alfred Perlstein To: Andrei Popov Cc: Dan Nelson , freebsd-questions@FreeBSD.ORG, freebsd-current@FreeBSD.ORG Subject: Re: Swap not used *at**all* Message-ID: <20011226131727.M91594@elvis.mu.org> References: <20011226091540.A70996@m-net.arbornet.org> <20011226151905.GA84869@dan.emsphone.com> <20011226124857.A30355@m-net.arbornet.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable User-Agent: Mutt/1.2.5i In-Reply-To: <20011226124857.A30355@m-net.arbornet.org>; from ceesaxp@m-net.arbornet.org on Wed, Dec 26, 2001 at 12:48:58PM -0500 Sender: owner-freebsd-questions@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG * Andrei Popov [011226 12:21] wrote: > On Wed, Dec 26, 2001 at 09:19:05AM -0600, Dan Nelson wrote: > > In the last episode (Dec 26), Andrei Popov said: > > >=20 > > > Is this normal: > > >=20 > > > andrei@vogon:~ > > > 2:05:49pm% swapinfo > > > Device 1K-blocks Used Avail Capacity Type > > > /dev/ad4s1b 525344 0 525344 0% Interleaved > > >=20 > > > This machine is running with 256MB RAM and a 512MB swap device. Swap= usage > > > is zero even when running X and postgress and aolserver with a running > > > instance of OpenACS-4. > >=20 > > Try this:=20 > >=20 > > dd if=3D/dev/zero of=3D/dev/null bs=3D192m count=3D1 > >=20 > > That should force some swapping :) >=20 > It sure does :) >=20 > But the question still remains -- is it not odd that there's no swapping > when running X, nor is there one when running fairly expenm=7Fsive Postgr= es > selects et al? No, the system tries pretty hard not to swap. In fact swapping is really a bad thing to have happen on a loaded machine as it can result in a cascade failure. If you look in the archives for Matt Dillon's postings on "cascade failure" it will explain things a lot better. --=20 -Alfred Perlstein [alfred@freebsd.org] 'Instead of asking why a piece of software is using "1970s technology," start asking why software is ignoring 30 years of accumulated wisdom.' Tax deductable donations for FreeBSD: http://www.freebsdfoundation.org/ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message