From owner-freebsd-fs@FreeBSD.ORG Wed Apr 27 11:13:50 2011 Return-Path: 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 9CB70106564A for ; Wed, 27 Apr 2011 11:13:50 +0000 (UTC) (envelope-from daniel@digsys.bg) Received: from smtp-sofia.digsys.bg (smtp-sofia.digsys.bg [193.68.3.230]) by mx1.freebsd.org (Postfix) with ESMTP id 2607B8FC0C for ; Wed, 27 Apr 2011 11:13:49 +0000 (UTC) Received: from dcave.digsys.bg (dcave.digsys.bg [192.92.129.5]) (authenticated bits=0) by smtp-sofia.digsys.bg (8.14.4/8.14.4) with ESMTP id p3RAtOP5083770 (version=TLSv1/SSLv3 cipher=DHE-RSA-CAMELLIA256-SHA bits=256 verify=NO) for ; Wed, 27 Apr 2011 13:55:29 +0300 (EEST) (envelope-from daniel@digsys.bg) Message-ID: <4DB7F61C.8060003@digsys.bg> Date: Wed, 27 Apr 2011 13:55:24 +0300 From: Daniel Kalchev User-Agent: Mozilla/5.0 (X11; U; FreeBSD amd64; en-US; rv:1.9.2.15) Gecko/20110307 Thunderbird/3.1.9 MIME-Version: 1.0 To: freebsd-fs@freebsd.org References: <20110427101728.49C801065709@hub.freebsd.org> In-Reply-To: <20110427101728.49C801065709@hub.freebsd.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: Why not just name the cam-ata devices the same as the old, names? X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 27 Apr 2011 11:13:50 -0000 This labeling issue has intrigued me recently, as ZFS has become more mature on FreeBSD. With ZFS, although you may have the same pool names on disks, you will not import the wrong zpool (unless you boot off it somehow) if you happen to have two pool with the same name in the system. The zpool has it's UUID and the zpool name is just for user's convenience. I believe, we could invent/adopt something similar for UFS labels as well. Now, the easiest answer for this device renaming problem is: use UFS labels. Or disk labels, as Freddie suggested. Or GPT partition labels. Or use GUUIDs instead (GPT or UFS) if you are paranoid. Why would it be a problem that UFS labels are gone, when you newfs the filesystem? Our intention to use labels is to preserve mount points across reboots, possible on different hardware (HBA). You don't keep the contents of the filesystem when you newfs it, so you may well provide newfs with the appropriate -L label. Or use new label if you will use the filesystem for a different purpose/mountpoint. What should be done, ideally before the 9.0 release is to find some sane resolution method of what happens when you happen to have two (for example) 'root' UFS labels during boot/mount time. Daniel