From owner-freebsd-scsi@FreeBSD.ORG Sun Sep 21 08:53:02 2014 Return-Path: Delivered-To: freebsd-scsi@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 84CA2C13 for ; Sun, 21 Sep 2014 08:53:02 +0000 (UTC) Received: from mout.gmx.net (mout.gmx.net [212.227.17.21]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "mout.gmx.net", Issuer "TeleSec ServerPass DE-1" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 1C391E6C for ; Sun, 21 Sep 2014 08:53:01 +0000 (UTC) Received: from mandree.no-ip.org ([78.48.101.189]) by mail.gmx.com (mrgmx101) with ESMTPSA (Nemesis) id 0LlYrb-1Y3Jg1041v-00bL4W for ; Sun, 21 Sep 2014 10:52:54 +0200 Received: from [IPv6:::1] (localhost6.localdomain6 [IPv6:::1]) by apollo.emma.line.org (Postfix) with ESMTP id 169B423D543 for ; Sun, 21 Sep 2014 10:52:53 +0200 (CEST) Message-ID: <541E91E4.4030802@gmx.de> Date: Sun, 21 Sep 2014 10:52:52 +0200 From: Matthias Andree User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.1.1 MIME-Version: 1.0 To: freebsd-scsi@freebsd.org Subject: Re: How to disable hard disk write cache? References: <541804B0.7070407@gmail.com> <54184484.1070304@delphij.net> <541E8DAE.8010407@gmx.de> <541E8F72.4020202@delphij.net> In-Reply-To: <541E8F72.4020202@delphij.net> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit X-Provags-ID: V03:K0:2IbUdxKjC4/itDNkDxip1siSJTy5getZUwUMSU3BzyH1dAsUgY1 H789ZwhNDm6ITxdtMolWHc0cRySwLeWrNdWncj3UjqzzJmiWsmRnOyKQVPFtIOEwvs300Ai L+dv44106hu7zLDo/Goim8Bftkne63ec9mfbT8714s7s5/dFb/Z/eH3FSEyAbgDT57k5Yvs EWflf89ui2/rumy0pidqw== X-UI-Out-Filterresults: notjunk:1; X-BeenThere: freebsd-scsi@freebsd.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: SCSI subsystem List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 21 Sep 2014 08:53:02 -0000 Am 21.09.2014 um 10:42 schrieb Xin Li: > On 9/21/14 4:34 PM, Matthias Andree wrote: >> Am 16.09.2014 um 16:09 schrieb Xin Li: > >>> Modern SATA/SAS/SCSI devices usually comes with the capability >>> of tagged commands, allowing the OS to know when a write buffer >>> is on stable storage. With this, file systems can easily >>> implement the right semantics and recover from e.g. a power >>> outage, etc. > >> Yes, they *can easily implement* that, but which file systems in >> FreeBSD *actually do* that? > > Both UFS (with Soft Updates, which is what it's all about; I haven't > checked the Journalled Soft Updates case) and ZFS do that for ages. Thank you. Is this in any of the 9.3 manpages so I could look that up rather than ask questions on the lists? :-)