From owner-freebsd-hackers@FreeBSD.ORG Fri Aug 19 12:50:40 2011 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id CDE3F106566C for ; Fri, 19 Aug 2011 12:50:40 +0000 (UTC) (envelope-from aled.w.morris@googlemail.com) Received: from mail-vw0-f54.google.com (mail-vw0-f54.google.com [209.85.212.54]) by mx1.freebsd.org (Postfix) with ESMTP id 863388FC15 for ; Fri, 19 Aug 2011 12:50:40 +0000 (UTC) Received: by vws18 with SMTP id 18so3089187vws.13 for ; Fri, 19 Aug 2011 05:50:39 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=googlemail.com; s=gamma; h=mime-version:sender:in-reply-to:references:date :x-google-sender-auth:message-id:subject:from:to:cc:content-type; bh=vPB9J7+cQLw0PeYFgrHvZcteaQOD4QHQFgekazFQjYA=; b=pbYZsNJKBpj2qxxZGTj8o3W69gNk6Sacl2cCJ3t+OEybt09s0z6tgN77mczu3NubNG pKG6pk6aVgj7SkQa9H2/2is6ABqxKLwmsjlC0KmDNUdBuE9v/bkV30TKoR/rXPHcdzn0 dfa0KfAnyk84BCoez9fc1r1nNVGXcOWD5nN14= MIME-Version: 1.0 Received: by 10.52.19.133 with SMTP id f5mr1993387vde.210.1313756460776; Fri, 19 Aug 2011 05:21:00 -0700 (PDT) Sender: aled.w.morris@googlemail.com Received: by 10.52.188.196 with HTTP; Fri, 19 Aug 2011 05:21:00 -0700 (PDT) In-Reply-To: References: <4E4D50CD.5080806@rawbw.com> Date: Fri, 19 Aug 2011 13:21:00 +0100 X-Google-Sender-Auth: iF3hnL331Pk_tgT2iKb_e2T_FRo Message-ID: From: Aled Morris To: Tom Evans Content-Type: text/plain; charset=ISO-8859-1 X-Content-Filtered-By: Mailman/MimeDel 2.1.5 Cc: Yuri , freebsd-hackers@freebsd.org Subject: Re: ZFS installs on HD with 4k physical blocks without any warning as on 512 block size device X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 19 Aug 2011 12:50:41 -0000 On 19 August 2011 11:15, Tom Evans wrote: > On Thu, Aug 18, 2011 at 6:50 PM, Yuri wrote: > > Some latest hard drives have logical sectors of 512 byte when they > actually > > have 4k physical sectors. > ... > Shouldn't UFS and ZFS drivers be able to either read the right sector size > > from the underlying device or at least issue a warning? > > The device never reports the actual sector size, so unless FreeBSD > keeps a database of 4k sector hard drives that report as 512 byte > sector hard drives, there is nothing that can be done. > > At what point should we change the default in newfs/zfs to 4k? I guess formatting the filesystem for 4k sectors on a 512b drive would still work but it would be suboptimal. What would the performance penalty be in reality? Aled