From owner-freebsd-fs@FreeBSD.ORG Tue Dec 20 10:03:47 2011 Return-Path: <owner-freebsd-fs@FreeBSD.ORG> 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 96FA91065679 for <freebsd-fs@FreeBSD.ORG>; Tue, 20 Dec 2011 10:03:47 +0000 (UTC) (envelope-from peterjeremy@acm.org) Received: from fallbackmx06.syd.optusnet.com.au (fallbackmx06.syd.optusnet.com.au [211.29.132.8]) by mx1.freebsd.org (Postfix) with ESMTP id 224D68FC13 for <freebsd-fs@FreeBSD.ORG>; Tue, 20 Dec 2011 10:03:45 +0000 (UTC) Received: from mail16.syd.optusnet.com.au (mail16.syd.optusnet.com.au [211.29.132.197]) by fallbackmx06.syd.optusnet.com.au (8.13.1/8.13.1) with ESMTP id pBK7vOew020514 for <freebsd-fs@FreeBSD.ORG>; Tue, 20 Dec 2011 18:57:27 +1100 Received: from server.vk2pj.dyndns.org (c220-239-116-103.belrs4.nsw.optusnet.com.au [220.239.116.103]) by mail16.syd.optusnet.com.au (8.13.1/8.13.1) with ESMTP id pBK7vHnQ031874 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Tue, 20 Dec 2011 18:57:18 +1100 X-Bogosity: Ham, spamicity=0.000000 Received: from server.vk2pj.dyndns.org (localhost.vk2pj.dyndns.org [127.0.0.1]) by server.vk2pj.dyndns.org (8.14.5/8.14.4) with ESMTP id pBK7vFaR035981; Tue, 20 Dec 2011 18:57:15 +1100 (EST) (envelope-from peter@server.vk2pj.dyndns.org) Received: (from peter@localhost) by server.vk2pj.dyndns.org (8.14.5/8.14.4/Submit) id pBK7vFoU035980; Tue, 20 Dec 2011 18:57:15 +1100 (EST) (envelope-from peter) Date: Tue, 20 Dec 2011 18:57:14 +1100 From: Peter Jeremy <peterjeremy@acm.org> To: Hugo Silva <hugo@barafranca.com> Message-ID: <20111220075714.GA35787@server.vk2pj.dyndns.org> References: <4EEF321E.5090806@barafranca.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="x+6KMIRAuhnl3hBn" Content-Disposition: inline In-Reply-To: <4EEF321E.5090806@barafranca.com> X-PGP-Key: http://members.optusnet.com.au/peterjeremy/pubkey.asc User-Agent: Mutt/1.5.21 (2010-09-15) Cc: freebsd-fs@FreeBSD.ORG Subject: Re: ZFS: root pool considerations, multiple pools on the same disk X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Filesystems <freebsd-fs.freebsd.org> List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-fs>, <mailto:freebsd-fs-request@freebsd.org?subject=unsubscribe> List-Archive: <http://lists.freebsd.org/pipermail/freebsd-fs> List-Post: <mailto:freebsd-fs@freebsd.org> List-Help: <mailto:freebsd-fs-request@freebsd.org?subject=help> List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-fs>, <mailto:freebsd-fs-request@freebsd.org?subject=subscribe> X-List-Received-Date: Tue, 20 Dec 2011 10:03:47 -0000 --x+6KMIRAuhnl3hBn Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On 2011-Dec-19 12:46:22 +0000, Hugo Silva <hugo@barafranca.com> wrote: >I've been thinking about whether it makes sense to separate the rpool >from the data pool(s).. I think it does. I have 6 1TB disks with 8GB carved off the front of each disk for root & swap. I initially used a separate (gmirrored) UFS root (including /usr/src and /usr/obj) because I didn't completely trust ZFS. I've since moved to a 3-way mirrored ZFS root, with the "root" area of the remaining 3 disks basically spare (I use them for upgrades). The bulk of the disks form a 6-way RAIDZ2 data pool. I still think having a separate root makes sense because it should simplify recovery if everything goes pear-shaped. >One idea would be creating a 4-way mirror on small partitions for the >rpool (sturdier), and a zfs raid-10 on the remaining larger partition. I'd recommend having two 2-way mirrored root pools that you update alternately. There are a couple of failure modes where it can be difficult to difficult to get back to a known working state without a second boot/root. >I'm curious about the performance implications (if any) of having >1 >zpools on the same disks (considering that during normal usage, it'll be >the data pool seeing 99.999% of the action) and whether anyone has >thought the same and/or applied this concept in production. I haven't done any performance comparisons but would expect this to be similar to having multiple UFS filesystems on one disk. --=20 Peter Jeremy --x+6KMIRAuhnl3hBn Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.18 (FreeBSD) iEYEARECAAYFAk7wP9oACgkQ/opHv/APuIeHlACfTT4yQqQFZCYpf1TZ3Y5B407L JIUAnR8dueaWQfZ9hGpv7gPIwgyP6mcM =Niwg -----END PGP SIGNATURE----- --x+6KMIRAuhnl3hBn--