From owner-freebsd-questions@FreeBSD.ORG Tue Oct 5 14:44:17 2004 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 8C48B16A4CE for ; Tue, 5 Oct 2004 14:44:17 +0000 (GMT) Received: from av6-1-sn2.hy.skanova.net (av6-1-sn2.hy.skanova.net [81.228.8.106]) by mx1.FreeBSD.org (Postfix) with ESMTP id 4F15643D3F for ; Tue, 5 Oct 2004 14:44:17 +0000 (GMT) (envelope-from ertr1013@student.uu.se) Received: by av6-1-sn2.hy.skanova.net (Postfix, from userid 502) id 23BB837E66; Tue, 5 Oct 2004 16:44:16 +0200 (CEST) Received: from smtp2-1-sn2.hy.skanova.net (smtp2-1-sn2.hy.skanova.net [81.228.8.177]) by av6-1-sn2.hy.skanova.net (Postfix) with ESMTP id 0EDF637E42 for ; Tue, 5 Oct 2004 16:44:16 +0200 (CEST) Received: from falcon.midgard.homeip.net (h201n1fls24o1048.bredband.comhem.se [212.181.162.201]) by smtp2-1-sn2.hy.skanova.net (Postfix) with SMTP id B5E3737E4A for ; Tue, 5 Oct 2004 16:44:15 +0200 (CEST) Received: (qmail 17340 invoked by uid 1001); 5 Oct 2004 14:44:15 -0000 Date: Tue, 5 Oct 2004 16:44:15 +0200 From: Erik Trulsson To: Rae Message-ID: <20041005144415.GA17317@falcon.midgard.homeip.net> Mail-Followup-To: Rae , freebsd-questions@freebsd.org References: <2ede6f3204100507344ba2f245@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <2ede6f3204100507344ba2f245@mail.gmail.com> User-Agent: Mutt/1.5.6i cc: freebsd-questions@freebsd.org Subject: Re: would async mount improve IO speed? X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 05 Oct 2004 14:44:17 -0000 On Tue, Oct 05, 2004 at 10:34:15AM -0400, Rae wrote: > File systems used to be mounted with soft-updates(?) option. > I disable it with "tunefs -n disable ....." and mount all file system > with "async" option but I can feel any difference. > some said it's dangerous. Does it matter even if I'm not running any > heavy load server? async (as well as soft-updates) only improve performance when writing to the disk. Reading from the file system will not be affected by either. "async" can be dangerous, yes. If the computer crashes, or is otherwise not properly shutdown, then you risk losing a *lot* of data from an async filesystem, as well as risking leaving the filesystem in an inconsistent state. "async" should only be used for filesystems where both the following holds true: 1) The system makes a lot of writes to the filesystem. (Otherwise there is very little performance gain to be obtained from "async".) 2) Losing all the data on the filesystem is not a big problem. -- Erik Trulsson ertr1013@student.uu.se