From owner-freebsd-stable@FreeBSD.ORG Mon Jun 15 15:54:56 2009 Return-Path: Delivered-To: freebsd-stable@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id DE09B1065670 for ; Mon, 15 Jun 2009 15:54:56 +0000 (UTC) (envelope-from fjwcash@gmail.com) Received: from yw-out-2324.google.com (yw-out-2324.google.com [74.125.46.31]) by mx1.freebsd.org (Postfix) with ESMTP id 923FB8FC1B for ; Mon, 15 Jun 2009 15:54:56 +0000 (UTC) (envelope-from fjwcash@gmail.com) Received: by yw-out-2324.google.com with SMTP id 9so2020162ywe.13 for ; Mon, 15 Jun 2009 08:54:55 -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; bh=7kqwmmAnAUlouvlg53Ae9+XSl4jD+yL/YefM2MR+S1g=; b=RJkIskbf3ZpFAJQtz0pXfQlFyUSbwDG/YWYhbpuDzKAH77cKxPqsCKEDfyWAqEjys3 10PSx/H0axEu9L15TB6TD3K3YbK8sCMxKc2OqXcOchtBbyVv570osoXNhutyKdqb0CnA E6GgrCf6hpAV0kHBvOpYe3TRh7dTIZU6UtWfg= 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; b=VVUF5Y/Lz+AKZpiNgD0fjwWEq8w+B26oYfAG3QnTgwx1JXNzrcYSkrYLmTgkkMddOs johQGZ4eNO22eZYwUFr9aUiSvsx5QGNn2Idc6STFaxWnQLW1C9HW899njFWNaSNBOpuZ dlVSWyAa/TRLNof98xUtk3nyU4bPUG7RC+0Ew= MIME-Version: 1.0 Received: by 10.151.68.9 with SMTP id v9mr13606103ybk.8.1245081295822; Mon, 15 Jun 2009 08:54:55 -0700 (PDT) In-Reply-To: <18998.27937.780804.279674@already.local> References: <18998.27937.780804.279674@already.local> Date: Mon, 15 Jun 2009 08:54:55 -0700 Message-ID: From: Freddie Cash To: hartzell@alerce.com Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Content-Filtered-By: Mailman/MimeDel 2.1.5 Cc: FreeBSD-STABLE Mailing List Subject: Re: Does this disk/filesystem layout look sane to you? X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 15 Jun 2009 15:54:57 -0000 On Mon, Jun 15, 2009 at 8:47 AM, George Hartzell wrote: > Freddie Cash writes: > > On Sun, Jun 14, 2009 at 9:17 AM, Dan Naumov > wrote: > > > > > I just wanted to have an extra pair (or a dozen) of eyes look this > > > configuration over before I commit to it (tested it in VMWare just in > > > case, it works, so I am considering doing this on real hardware soon). > > > I drew a nice diagram: http://www.pastebin.ca/1460089 Since it doesnt > > > show on the diagram, let me clarify that the geom mirror consumers as > > > well as the vdevz for ZFS RAIDZ are going to be partitions (raw disk > > > => full disk slice => swap partition | mirror provider partition | zfs > > > vdev partition | unused. > > > > > > I don't know for sure if it's the same on FreeBSD, but on Solaris, ZFS > will > > disable the onboard disk cache if the vdevs are not whole disks. IOW, > if > > you use slices, partitions, or files, the onboard disk cache is > disabled. > > This can lead to poor write performance. > > > > Unless you can use one of the ZFS-on-root facilities, I'd look into > getting > > a couple of CompactFlash or USB sticks to use for the gmirror for / and > /usr > > (put the rest on ZFS). Then you can dedicate the entirety of all 5 > drives > > to ZFS. > > Even if you use do a bootable ZFS on root, you'll end up with a couple > of gpt partitions (boot code, swap, then root) and therefor > constructing your ZFS file system from a partition. > > Pawel said, back on April 6, 2007, > > "We support cache flushing operations on any GEOM provider (disk, > partition, slice, anything disk-like), so bascially currently I > treat everything as a whole disk [...]" > > Does anyone know for sure if we disable caching for partitions? > Going back through some old threads, it seems that I was mistaken, and it's only on Solaris that disk cache is disabled for vdevs created from partitions. 3 cheers for GEOM. :) -- Freddie Cash fjwcash@gmail.com