From owner-freebsd-hackers Sat Aug 24 18:34:40 1996 Return-Path: owner-hackers Received: (from root@localhost) by freefall.freebsd.org (8.7.5/8.7.3) id SAA20327 for hackers-outgoing; Sat, 24 Aug 1996 18:34:40 -0700 (PDT) Received: from ottawa.net (ppp-62.ottawa.net [205.211.4.62]) by freefall.freebsd.org (8.7.5/8.7.3) with ESMTP id SAA20318 for ; Sat, 24 Aug 1996 18:34:35 -0700 (PDT) Received: (from brianc@localhost) by ottawa.net (8.7.5/8.7.3) id VAA00204 for freebsd-hackers@FreeBSD.org; Sat, 24 Aug 1996 21:34:24 -0400 (EDT) From: Brian Campbell Message-Id: <199608250134.VAA00204@ottawa.net> Subject: Re: Multiple swaps slow down system? To: freebsd-hackers@FreeBSD.org (FreeBSD Hackers) Date: Sat, 24 Aug 1996 21:34:24 -0400 (EDT) In-Reply-To: <199608241902.MAA05377@MindBender.serv.net> from "Michael L. VanLoon" at "Aug 24, 96 12:02:58 pm" Reply-to: brianc@pobox.com X-Mailer: ELM [version 2.4ME+ PL22 (25)] MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-hackers@FreeBSD.org X-Loop: FreeBSD.org Precedence: bulk > >Due to some debate in one of the usenet I decided to try using > >multiple swap partitions, one on an IDE drive and the other on a SCSI > >drive, to see if it increased performance. I can't say I noticed > >any performance increase while using the system. > >However, I find it takes several times longer for a shutdown to > >complete. Is there any logic to that? > > I don't know why that happens, but I wouldn't expect it to give you > much of a performance boost, since IDE doesn't do asynchronous I/O (at > least under *BSD anyway). If you have a very busy system, I would > expect it to give you a performance drop, in fact. Oh? There's no busmastering IDE support yet? Is it in the works? Would you suggesting using SCSI for swap even if the IDE drive has 50% higher throughput? Is latency an issue? Any hints for finding out why w/ swap on either IDE or SCSI, shutdown takes less than 15s, but when using both it takes more than 60s?