From owner-freebsd-fs@FreeBSD.ORG Thu Jan 24 08:34:30 2013 Return-Path: Delivered-To: freebsd-fs@freebsd.org Received: from mx1.freebsd.org (mx1.FreeBSD.org [8.8.178.115]) by hub.freebsd.org (Postfix) with ESMTP id 55D582B4 for ; Thu, 24 Jan 2013 08:34:30 +0000 (UTC) (envelope-from borjam@sarenet.es) Received: from proxypop04.sare.net (proxypop04.sare.net [194.30.0.65]) by mx1.freebsd.org (Postfix) with ESMTP id 198DBEBE for ; Thu, 24 Jan 2013 08:34:29 +0000 (UTC) Received: from [172.16.2.2] (izaro.sarenet.es [192.148.167.11]) by proxypop04.sare.net (Postfix) with ESMTPSA id 5DF2F9DD778; Thu, 24 Jan 2013 09:27:06 +0100 (CET) Subject: Re: RFC: Suggesting ZFS "best practices" in FreeBSD Mime-Version: 1.0 (Apple Message framework v1085) Content-Type: text/plain; charset=us-ascii From: Borja Marcos In-Reply-To: <20130123143018.GA5533@roberto02-aw.eurocontrol.fr> Date: Thu, 24 Jan 2013 09:27:14 +0100 Content-Transfer-Encoding: quoted-printable Message-Id: <0AF9A29D-5B5A-4CB6-B880-7F43CA7FC612@sarenet.es> References: <314B600D-E8E6-4300-B60F-33D5FA5A39CF@sarenet.es> <20130123143018.GA5533@roberto02-aw.eurocontrol.fr> To: Ollivier Robert X-Mailer: Apple Mail (2.1085) Cc: freebsd-fs@freebsd.org X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 24 Jan 2013 08:34:30 -0000 On Jan 23, 2013, at 3:30 PM, Ollivier Robert wrote: > According to Freddie Cash on Tue, Jan 22, 2013 at 03:02:40PM -0800: >> The ZFS metadata on disk allows you to move disks around in a system = and >> still import the pool, correct. >=20 > Even better, a few years ago before I enabled AHCI on my machine, the > drives were named adX. After I started using AHCI, the drives became = adaY > and it still booted fine. Yes, that's right. As an example, yesterday I used the gnop kludge to = have a SSD recognized as a 4K-sector drive. After a reboot,=20 ZFS was able to locate the device even though the named gnop device had = disappeared. However, remember that the Murphy's field is enormously intense around = anything that holds data, especially if that data is important. Yes, it works, but it's better not to rely = too much on error recovery mechanisms. And there is at least one situation in which the dynamic renumbering causes trouble = (failure + reboot) which is not so rare on=20 high uptime machines with many disks. Borja.