From owner-freebsd-current@FreeBSD.ORG Mon Dec 28 11:58:29 2009 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 96A8B1065670; Mon, 28 Dec 2009 11:58:29 +0000 (UTC) (envelope-from 000.fbsd@quip.cz) Received: from elsa.codelab.cz (elsa.codelab.cz [94.124.105.4]) by mx1.freebsd.org (Postfix) with ESMTP id 51A1C8FC1C; Mon, 28 Dec 2009 11:58:29 +0000 (UTC) Received: from localhost (localhost.codelab.cz [127.0.0.1]) by elsa.codelab.cz (Postfix) with ESMTP id 7DC9F19E045; Mon, 28 Dec 2009 12:58:27 +0100 (CET) Received: from [192.168.1.2] (r5bb235.net.upc.cz [86.49.61.235]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by elsa.codelab.cz (Postfix) with ESMTPSA id 0FFCE19E044; Mon, 28 Dec 2009 12:58:25 +0100 (CET) Message-ID: <4B389D60.7000005@quip.cz> Date: Mon, 28 Dec 2009 12:58:24 +0100 From: Miroslav Lachman <000.fbsd@quip.cz> User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:1.9.1.6) Gecko/20091206 SeaMonkey/2.0.1 MIME-Version: 1.0 To: Alexander Motin References: <4B349ABF.2070800@FreeBSD.org> <469FFFC8-514B-41B9-AEEC-E4B7AB6CB886@exscape.org> <4B34A183.7000909@FreeBSD.org> In-Reply-To: <4B34A183.7000909@FreeBSD.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: FreeBSD-Current , Thomas Backman , freebsd-arch@freebsd.org Subject: Re: File system blocks alignment X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 28 Dec 2009 11:58:29 -0000 Alexander Motin wrote: > Thomas Backman wrote: >> On Dec 25, 2009, at 11:58 AM, Alexander Motin wrote: > |>> Recently WD released first series of ATA disks with increased physical >>> sector size. It makes writes not matching with 4K blocks inefficient >>> there. >> They don't expose this to the OS, though (not by default, anyway), but chop it up into 8 512-byte sectors for compatibility reasons. >> Just thought I'd point that out - I'm not even sure if you can get them to *not* do the compatibility thing and expose 4k-sized sectors. > > Latest ATA-8 specification allows drive to report both logical (512B) > and physical (4KB) sector sizes. ada driver able to fetch and report > that info to GEOM. If these drives not reporting it yet (are you really > sure?), it is only question of their firmware. There is an article about 4k sectors http://www.anandtech.com/storage/showdoc.aspx?i=3691 It is completely hidden to OS in first versions. Miroslav Lachman