From owner-freebsd-fs@FreeBSD.ORG Tue Jan 3 16:24:30 2012 Return-Path: Delivered-To: freebsd-fs@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id B57161065749 for ; Tue, 3 Jan 2012 16:24:30 +0000 (UTC) (envelope-from jdc@koitsu.dyndns.org) Received: from qmta14.emeryville.ca.mail.comcast.net (qmta14.emeryville.ca.mail.comcast.net [76.96.27.212]) by mx1.freebsd.org (Postfix) with ESMTP id 9AA108FC1B for ; Tue, 3 Jan 2012 16:24:30 +0000 (UTC) Received: from omta17.emeryville.ca.mail.comcast.net ([76.96.30.73]) by qmta14.emeryville.ca.mail.comcast.net with comcast id H4Mn1i0081afHeLAE4QPlJ; Tue, 03 Jan 2012 16:24:23 +0000 Received: from koitsu.dyndns.org ([67.180.84.87]) by omta17.emeryville.ca.mail.comcast.net with comcast id H3gX1i00a1t3BNj8d3gXrc; Tue, 03 Jan 2012 15:40:31 +0000 Received: by icarus.home.lan (Postfix, from userid 1000) id C9594102C19; Tue, 3 Jan 2012 08:24:28 -0800 (PST) Date: Tue, 3 Jan 2012 08:24:28 -0800 From: Jeremy Chadwick To: Peter Maloney Message-ID: <20120103162428.GA18661@icarus.home.lan> References: <4F003EB8.6080006@dannysplace.net> <4F02FC42.1040103@dannysplace.net> <4F0311F2.7050209@brockmann-consult.de> <4F0312DF.8050004@brockmann-consult.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4F0312DF.8050004@brockmann-consult.de> User-Agent: Mutt/1.5.21 (2010-09-15) Cc: freebsd-fs@freebsd.org Subject: Re: ZFS With Gpart partitions X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 03 Jan 2012 16:24:30 -0000 On Tue, Jan 03, 2012 at 03:38:23PM +0100, Peter Maloney wrote: > On 01/03/2012 03:34 PM, Peter Maloney wrote: > > On 01/03/2012 02:01 PM, Dan Carroll wrote: > >> On 3/01/2012 10:27 PM, krad wrote: > >>> Just a not you dont appear to be 4k aligned on this drive. As the > >>> drive capacity is > 1.5 Tb you probably should be. You will also be > >>> ashift=9 as well. This may or may not be a problem for you. > >> That was intentional, as I *thought* these drives were not 4k sector > >> drives. I am not sure how I am supposed to tell. They are WD RE4 > >> drives. > >> I confess, however to knowing nothing about ashift=9..... Could you > >> elaborate? > > Read this thread: > > > > ZFS using 'advanced format drives' with FreeBSD (8.2-RC3) > > http://forums.freebsd.org/showthread.php?t=21644 > > > > (and of course don't play around and run the dd command, etc. for disks > > with valuable data on them) > > > And looking at dmesg or /var/log/messages should probably tell you what > your sector size is. > > eg. > # dmesg | grep "da2:" > > or > > # grep "da2:" /var/log/messages > > or > > # bunzip2 -c /var/log/messages.1.bz2 | grep "da2:" > Nov 28 13:59:35 bcnas1 kernel: da2: Fixed Direct > Access SCSI-6 device > Nov 28 13:59:35 bcnas1 kernel: da2: 600.000MB/s transfers > Nov 28 13:59:35 bcnas1 kernel: da2: Command Queueing enabled > Nov 28 13:59:35 bcnas1 kernel: da2: 2861588MB (5860533168 *512 byte > sectors*: 255H 63S/T 364801C) This is incorrect. Most 4KB sector drives advertise a logical sector size of 512 (this is to maintain/guarantee full compatibility with older OSes and existing software), while sometimes advertising a physical sector size of 4096. Comparatively, Intel SSDs advertise both a logical and physical sector size of 512, even though we all know better. Use either "camcontrol identify" or "camcontrol inquiry" (which command depends on if you're using SATA-via-CAM or native SCSI) to find out. If this doesn't work for you, try using smartmontools (if there's a difference between logical/physical it will display both, otherwise it'll say "logical/physical" literally). -- | Jeremy Chadwick jdc at parodius.com | | Parodius Networking http://www.parodius.com/ | | UNIX Systems Administrator Mountain View, CA, US | | Making life hard for others since 1977. PGP 4BD6C0CB |