From owner-freebsd-stable@FreeBSD.ORG Wed Sep 2 08:33:59 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 041BC106566C for ; Wed, 2 Sep 2009 08:33:59 +0000 (UTC) (envelope-from serenity@exscape.org) Received: from ch-smtp01.sth.basefarm.net (ch-smtp01.sth.basefarm.net [80.76.149.212]) by mx1.freebsd.org (Postfix) with ESMTP id 8354F8FC13 for ; Wed, 2 Sep 2009 08:33:58 +0000 (UTC) Received: from c83-253-252-234.bredband.comhem.se ([83.253.252.234]:60004 helo=mx.exscape.org) by ch-smtp01.sth.basefarm.net with esmtp (Exim 4.68) (envelope-from ) id 1MilHl-0007AN-3a; Wed, 02 Sep 2009 10:33:47 +0200 Received: from [192.168.1.5] (macbookpro [192.168.1.5]) (using TLSv1 with cipher AES128-SHA (128/128 bits)) (No client certificate requested) by mx.exscape.org (Postfix) with ESMTPSA id A4BC71A2876; Wed, 2 Sep 2009 10:33:25 +0200 (CEST) Mime-Version: 1.0 (Apple Message framework v1075.2) Content-Type: text/plain; charset=us-ascii; format=flowed; delsp=yes From: Thomas Backman In-Reply-To: <4A9E2C7C.6030904@mapper.nl> Date: Wed, 2 Sep 2009 10:33:24 +0200 Content-Transfer-Encoding: 7bit Message-Id: References: <061541E3-F301-46C4-8ECB-5B05854F0EAA@exscape.org> <4A9D558A.9070609@quip.cz> <4A9E1CB5.6030906@mapper.nl> <20090902074445.GA13588@dmr.ath.cx> <4A9E2C7C.6030904@mapper.nl> To: Mark Stapper X-Mailer: Apple Mail (2.1075.2) X-Originating-IP: 83.253.252.234 X-Scan-Result: No virus found in message 1MilHl-0007AN-3a. X-Scan-Signature: ch-smtp01.sth.basefarm.net 1MilHl-0007AN-3a 0d09b6b9d32a5e2a1232350a7bc8ce2f Cc: freebsd-stable@freebsd.org, Emil Mikulic , Miroslav Lachman <000.fbsd@quip.cz>, Maciej Jan Broniarz Subject: Re: zfs on gmirror slice 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: Wed, 02 Sep 2009 08:33:59 -0000 On Sep 2, 2009, at 10:27 AM, Mark Stapper wrote: > Emil Mikulic wrote: >> On Wed, Sep 02, 2009 at 09:20:21AM +0200, Mark Stapper wrote: >> >>> updating a zfs filesystem which you are running from is next to >>> impossible. >>> >> >> [citation needed] :) >> > Well, to update your zfs filesystem version, the filesystem is first > unmounted, then updated, and then mounted again. > citation coming up! > # umount / > umount: unmount of / failed: Invalid argument Nothing a LiveCD or something to that regard can't handle. Obviously this doesn't work for everyone, but it should for many. >> >>> So, i would recommend setting up gmirror to mirror your whole disks, >>> install the base system(boot and "world") on a small UFS slice, >>> and use >>> the rest of the disc as zfs slice. >>> >> >> As Thomas Backman pointed out, this means you won't get self-healing. >> > self-healing sounds very nice, but with mirrorring you have data on > two > discs, so in that case there no "healing" involved, it's just > checksumming and reading the non-corrupted copy. > From the gmirror manpage: "All operations like failure detection, > stale > component detection, rebuild of stale components, etc. are also done > automatically." > This would indicate the same functionality, with a much less fancy > name. > However, i have not tested it the way they demonstrate zfs's > "self-healing" property. > I might, if I get the time to run it in a virtual machine one of these > days.. If ZFS finds a corrupted copy and a non-corrupted one in a mirrored ZFS pool, it will repair the damage so that both copies are valid, so yes, self-healing will indeed occur. :) Regards, Thomas