From owner-freebsd-stable@FreeBSD.ORG Fri Feb 17 15:21:46 2012 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 A625910656D1 for ; Fri, 17 Feb 2012 15:21:46 +0000 (UTC) (envelope-from fjwcash@gmail.com) Received: from mail-vx0-f182.google.com (mail-vx0-f182.google.com [209.85.220.182]) by mx1.freebsd.org (Postfix) with ESMTP id 5EDDC8FC15 for ; Fri, 17 Feb 2012 15:21:46 +0000 (UTC) Received: by vcmm1 with SMTP id m1so3394318vcm.13 for ; Fri, 17 Feb 2012 07:21:45 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; bh=mZ57Que6JtCGvIiTjUjlqoouZHxk/W0LWvpCheegYvE=; b=IcvzztwsjIeGpoc7u+PDvAfkBNwdwrBuwHdz2v24IdzcopnyBOJr3Q7s26Ybx1cp/R xAAT4V+CJ4uI4foP6NWSDV1cL5YxRHxx/plBlfjxpLAXaouFQuyYunN50SVBpNYDHM4E yx/ubTQ91tWLniQx4FRDRa8Fh0HJ8Y6pj02xE= MIME-Version: 1.0 Received: by 10.52.38.10 with SMTP id c10mr3324547vdk.58.1329492105763; Fri, 17 Feb 2012 07:21:45 -0800 (PST) Received: by 10.220.192.135 with HTTP; Fri, 17 Feb 2012 07:21:45 -0800 (PST) In-Reply-To: References: <20120217030806.GA62601@icarus.home.lan> Date: Fri, 17 Feb 2012 07:21:45 -0800 Message-ID: From: Freddie Cash To: Pete French Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Cc: wblock@wonkity.com, freebsd-stable@freebsd.org, mandrews@bit0.com, 000.fbsd@quip.cz, freebsd@jdc.parodius.com Subject: Re: New BSD Installer 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: Fri, 17 Feb 2012 15:21:46 -0000 On Fri, Feb 17, 2012 at 3:12 AM, Pete French wr= ote: >> I wasn't aware you could do that. =C2=A0I was only aware that it was the >> other way around. =C2=A0That (my) misconception seems to also be relayed >> by others such as Miroslav who said: > > Should this not be the recommended way of doing things even for MBR > disks ? I have a lot of machines booting from gmirror, but we always > do it by mirroring MBR partitions (or GPT ones). I cant see why you would > want to do it the other way round in fact. It doesnt gain you anything > does it ? The problem with mirroring partitions is that you thrash the disk during the rebuild after replacing a failed disk. And the more partitions you have, the worse it gets. If you mirror the device, then the rebuild process only has to rebuild a single "thing". If you mirror 4 partitions on a device, then there will be four simultaneous, parallel rebuild processes running, thrashing the drive heads on both devices, killing you I/O throughput and extending the length of the rebuild. And if you mix your redundancy technologies (like gmirror and zfs mirror) it gets even worse due to competing rebuild schedulers. --=20 Freddie Cash fjwcash@gmail.com