From owner-freebsd-performance@FreeBSD.ORG Tue Jun 27 08:15:37 2006 Return-Path: X-Original-To: freebsd-performance@freebsd.org Delivered-To: freebsd-performance@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id D4DF916A401 for ; Tue, 27 Jun 2006 08:15:37 +0000 (UTC) (envelope-from leo.huang.gd@gmail.com) Received: from ug-out-1314.google.com (ug-out-1314.google.com [66.249.92.168]) by mx1.FreeBSD.org (Postfix) with ESMTP id 10B5743D69 for ; Tue, 27 Jun 2006 08:15:32 +0000 (GMT) (envelope-from leo.huang.gd@gmail.com) Received: by ug-out-1314.google.com with SMTP id m3so1394975uge for ; Tue, 27 Jun 2006 01:15:31 -0700 (PDT) DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=Y4cQ90V23PC60n0/L48D14+elORtdlksx3m0dLaY8LmBj1HAVZkin09wtnrDWdJ/FWZScPAiWurSHcMIzyiX3VD0ETdFFeKkYI20nlnVN8C2sWahv12qg1JMYYizK0Lh65xpJYd2RC94HtJ2TAfx6Q/5E3MTK9TLDrLmrbsrU5Q= Received: by 10.67.93.6 with SMTP id v6mr5791403ugl; Tue, 27 Jun 2006 01:15:31 -0700 (PDT) Received: by 10.67.27.12 with HTTP; Tue, 27 Jun 2006 01:15:31 -0700 (PDT) Message-ID: Date: Tue, 27 Jun 2006 16:15:31 +0800 From: "Leo Huang" To: "R. B. Riddick" In-Reply-To: <20060627074146.7400.qmail@web30311.mail.mud.yahoo.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <20060627033412.GQ10845@wantadilla.lemis.com> <20060627074146.7400.qmail@web30311.mail.mud.yahoo.com> Cc: freebsd-performance@freebsd.org, leo huang Subject: Re: Is the fsync() fake on FreeBSD6.1? X-BeenThere: freebsd-performance@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Performance/tuning List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 27 Jun 2006 08:15:37 -0000 hi, Arne, > You could do this test: > 1. write some data with dd if=/dev/zero of=/tmp/a bs=1m count=100 > 2. then fsync /tmp/a > 3. then listen to the hard disc > 4. repeat it until u r sure, if the hard disc reacts on the fsync command... > :-) Good idea. But the room is noisy. I think I can not hear. :-( > I do not know, if it is possible to turn off the write cache of a SCSI disc... How can I hnow whether the write cache is turned off? 2006/6/27, R. B. Riddick : > On Tuesday, 27 June 2006 at 10:18:47 +0800, leo huang wrote:me > > And how I can confirm this? > > > You could do this test: > 1. write some data with dd if=/dev/zero of=/tmp/a bs=1m count=100 > 2. then fsync /tmp/a > 3. then listen to the hard disc > 4. repeat it until u r sure, if the hard disc reacts on the fsync command... > :-) > > I do not know, if it is possible to turn off the write cache of a SCSI disc... > > On the freebsd-geom@ list was something about a new feature (the BIO_FLUSH > request), that can flush the write caches of hard discs. But it just works for > ata and amr discs currently... See: > http://docs.freebsd.org/cgi/getmsg.cgi?fetch=3624+0+archive/2006/freebsd-geom/20060625.freebsd-geom > > -Arne > > > __________________________________________________ > Do You Yahoo!? > Tired of spam? Yahoo! Mail has the best spam protection around > http://mail.yahoo.com > _______________________________________________ > freebsd-performance@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-performance > To unsubscribe, send any mail to "freebsd-performance-unsubscribe@freebsd.org" >