From owner-freebsd-questions@FreeBSD.ORG Tue Dec 3 17:37:12 2013 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 9B8A511A for ; Tue, 3 Dec 2013 17:37:12 +0000 (UTC) Received: from relaygateway02.edpnet.net (relaygateway02.edpnet.net [212.71.1.211]) by mx1.freebsd.org (Postfix) with ESMTP id 3749A141A for ; Tue, 3 Dec 2013 17:37:11 +0000 (UTC) X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: AooHANoVnlJNbXbJ/2dsb2JhbABagwc4g020VAEBSU6BGhd0giUBAQEDAQEBASArCBgLEAsOCgICBRMOAgIPBRMBCQgkCAcEARwEh1oKCbEfiUyGUBeBKYxqGgEBTweCazWBEwOVRYJOAYEwkGODKjsxgQQ X-IPAS-Result: AooHANoVnlJNbXbJ/2dsb2JhbABagwc4g020VAEBSU6BGhd0giUBAQEDAQEBASArCBgLEAsOCgICBRMOAgIPBRMBCQgkCAcEARwEh1oKCbEfiUyGUBeBKYxqGgEBTweCazWBEwOVRYJOAYEwkGODKjsxgQQ X-IronPort-AV: E=Sophos;i="4.93,819,1378850400"; d="scan'208";a="209735710" Received: from 77.109.118.201.adsl.dyn.edpnet.net (HELO mordor.lan) ([77.109.118.201]) by relaygateway02.edpnet.net with ESMTP/TLS/DHE-RSA-AES256-SHA; 03 Dec 2013 18:21:23 +0100 Date: Tue, 3 Dec 2013 18:37:00 +0100 From: Julien Cigar To: Warren Block Subject: Re: gmirror, gpart and MBR vs GPT in the Handbook Message-ID: <20131203173700.GD86280@mordor.lan> References: <201311301303210813.05DE187E@smtp.24cl.home> <201312011121580096.005D00FB@smtp.24cl.home> <20131202103122.GN66981@mordor.lan> <20131203092604.GA86280@mordor.lan> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.22 (2013-10-16) Cc: "Mike." , freebsd-questions@freebsd.org X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.17 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 03 Dec 2013 17:37:12 -0000 On Tue, Dec 03, 2013 at 09:27:12AM -0700, Warren Block wrote: > On Tue, 3 Dec 2013, Julien Cigar wrote: > > > On Mon, Dec 02, 2013 at 08:56:13AM -0700, Warren Block wrote: > >> On Mon, 2 Dec 2013, Julien Cigar wrote: > >> > >>> If you want to use GPT with gmirror you may want to mirror each > >>> partition instead of the whole disk. > >>> > >>> For example on my box I have the following: https://dpaste.de/Rb3S > >> > >> There are a couple of potential problems with that. The big one is when > >> a disk fails and is replaced. If you're not careful, the rebuild of all > >> those mirrored partitions will start at the same time. Head contention > >> will bring that to a near-standstill. It also puts a heavy load on the > >> drive that still works. Hopefully it is not the same model and age as > >> the one that failed, or its "warranty timer" may also be close to > >> expiring. > > > > That's true, I turned off autosynchronization of stale components to > > avoid this kind of bad scenario .. > > > >> > >> A less-serious problem is that only the partitions are mirrored. That > >> leaves out metadata like the partition tables and bootcode, but those > >> typically do not change very often and might not be a problem. The > >> admin has to remember to manually install such things on a new > >> replacement disk, though. > > > > It's just a matter of gpart backup / gpart restore, right ? > > That will get the partition tables but not the bootcode or PMBR. A > failed disk could then leave a mirror which has all the data but is > unbootable. ok, so I've to be sure that: $> gpart bootcode -b /boot/pmbr -p gptboot -i 1 adaX is executed for each disk involved in the mirror, right ..? > > At some point, we'll have to address the conflict between gmirror and > GPT. ZFS mirrors can replace gmirror in some situations, but not all. > _______________________________________________ > freebsd-questions@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-questions > To unsubscribe, send any mail to "freebsd-questions-unsubscribe@freebsd.org" -- No trees were killed in the creation of this message. However, many electrons were terribly inconvenienced.