From owner-freebsd-fs@FreeBSD.ORG Tue Jan 22 15:04:44 2013 Return-Path: Delivered-To: freebsd-fs@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by hub.freebsd.org (Postfix) with ESMTP id B1931123 for ; Tue, 22 Jan 2013 15:04:44 +0000 (UTC) (envelope-from wblock@wonkity.com) Received: from wonkity.com (wonkity.com [67.158.26.137]) by mx1.freebsd.org (Postfix) with ESMTP id 6502FB6E for ; Tue, 22 Jan 2013 15:04:44 +0000 (UTC) Received: from wonkity.com (localhost [127.0.0.1]) by wonkity.com (8.14.6/8.14.6) with ESMTP id r0MF4hpP061802; Tue, 22 Jan 2013 08:04:43 -0700 (MST) (envelope-from wblock@wonkity.com) Received: from localhost (wblock@localhost) by wonkity.com (8.14.6/8.14.6/Submit) with ESMTP id r0MF4gYT061799; Tue, 22 Jan 2013 08:04:42 -0700 (MST) (envelope-from wblock@wonkity.com) Date: Tue, 22 Jan 2013 08:04:42 -0700 (MST) From: Warren Block To: Borja Marcos Subject: Re: RFC: Suggesting ZFS "best practices" in FreeBSD In-Reply-To: <314B600D-E8E6-4300-B60F-33D5FA5A39CF@sarenet.es> Message-ID: References: <314B600D-E8E6-4300-B60F-33D5FA5A39CF@sarenet.es> User-Agent: Alpine 2.00 (BSF 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.2.7 (wonkity.com [127.0.0.1]); Tue, 22 Jan 2013 08:04:43 -0700 (MST) Cc: FreeBSD Filesystems , Scott Long 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: Tue, 22 Jan 2013 15:04:44 -0000 On Tue, 22 Jan 2013, Borja Marcos wrote: > 1- Dynamic disk naming -> We should use static naming (GPT labels, for instance) > > ZFS was born in a system with static device naming (Solaris). When you plug a disk it gets a fixed name. As far as I know, at least from my experience with Sun boxes, c1t3d12 is always c1t3d12. FreeBSD's dynamic naming can be very problematic. > > For example, imagine that I have 16 disks, da0 to da15. One of them, say, da5, dies. When I reboot the machine, all the devices from da6 to da15 will be renamed to the device number -1. Potential for trouble as a minimum. > > After several different installations, I am preferring to rely on static naming. Doing it with some care can really help to make pools portable from one system to another. I create a GPT partition in each drive, and Iabel it with a readable name. Thus, imagine I label each big partition (which takes the whole available space) as pool-vdev-disk, for example, pool-raidz1-disk1. I'm a proponent of using various types of labels, but my impression after a recent experience was that ZFS metadata was enough to identify the drives even if they were moved around. That is, ZFS bare metadata on a drive with no other partitioning or labels. Is that incorrect?