From owner-freebsd-fs@FreeBSD.ORG Wed Jun 17 20:58:41 2009 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 14FDB106567A for ; Wed, 17 Jun 2009 20:58:41 +0000 (UTC) (envelope-from dan.naumov@gmail.com) Received: from mail-yx0-f200.google.com (mail-yx0-f200.google.com [209.85.210.200]) by mx1.freebsd.org (Postfix) with ESMTP id BFF428FC1F for ; Wed, 17 Jun 2009 20:58:40 +0000 (UTC) (envelope-from dan.naumov@gmail.com) Received: by yxe38 with SMTP id 38so818945yxe.3 for ; Wed, 17 Jun 2009 13:58:40 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:received:in-reply-to:references :date:message-id:subject:from:to:cc:content-type :content-transfer-encoding; bh=NsRph5QurfkNaFuRhythdVWD1uMffj+7cN0LjatZRrI=; b=t5QY4BYdpjFvmEzDek+u6G4Ty85cRu4ZU337H91vnddydb7hXRhvBkdxwXJa4l4kPG nIWuR5IkMoUnnCNqfEHB49SMeMmMOhMxcvm+qpyOy288+q+wfzMw935JRkv18x1O/Thk 1bhHQs6oVqlTAR0h/eV+NBbXaqOFlu7bc1YVw= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; b=MB8hi8lnZLiY36pfoI7M93sVFhOmaR8kGX0asIuhP3Ls2ecEkXiJSjHPIQCCAT1YLb snDoT9QrM9spxpngerV3+ZTJJif/IaI7RoGDRnJIRx5vhOYvm46FeBMxtTfHR3CXGBvp 78OKHHVZbWMwDXwSh+ftJc1BtnRJNjlQeoDLM= MIME-Version: 1.0 Received: by 10.100.141.15 with SMTP id o15mr899564and.20.1245272319987; Wed, 17 Jun 2009 13:58:39 -0700 (PDT) In-Reply-To: <8663eu8u4l.fsf@pmade.com> References: <86ljnxyy01.fsf@pmade.com> <4A32CF01.4010004@barryp.org> <8663eu8u4l.fsf@pmade.com> Date: Wed, 17 Jun 2009 23:58:39 +0300 Message-ID: From: Dan Naumov To: Peter Jones Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: freebsd-fs@freebsd.org Subject: Re: Logical Disk to Physical Drive Mapping 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: Wed, 17 Jun 2009 20:58:43 -0000 You could use ZFS on a slice/partition taking up 99,9% of the disk's size to avoid this. Contrary to how it works in Solaris/OpenSolaris, in FreeBSD you don't use the ability to use write cache if you chose to use a slice or partition as a vdev for a ZFS pool instead of giving it the full disk. Additionally, you get some room to play if one disk in your raidz drop dead and your replacement drive ends up being a few sectors smaller then the disk you are replacing. - Dan Naumov On Wed, Jun 17, 2009 at 11:47 PM, Peter Jones wrote: > I'm not exactly sure how file system labels differ from disk labels, but > the man page suggests that they both write meta-data to the last sector > of the disk. > > Wouldn't that indicate that once ZFS wrote to the last sector of the > disk you'd loose that meta-data?