From owner-freebsd-stable@FreeBSD.ORG Tue Feb 9 17:10:22 2010 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 E855F106566B for ; Tue, 9 Feb 2010 17:10:22 +0000 (UTC) (envelope-from fjwcash@gmail.com) Received: from mail-iw0-f172.google.com (mail-iw0-f172.google.com [209.85.223.172]) by mx1.freebsd.org (Postfix) with ESMTP id 943838FC16 for ; Tue, 9 Feb 2010 17:10:22 +0000 (UTC) Received: by iwn2 with SMTP id 2so6205iwn.8 for ; Tue, 09 Feb 2010 09:10:22 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:received:in-reply-to:references :date:message-id:subject:from:to:content-type; bh=My9J3RT1Mxel4pw5lyAPAxknqPDMTmsP4BG9vqTiGJQ=; b=amNPZYhvpJBbG5MJfbiT7zsIjR5D2gnBuUd6N2P4NxMZuwqYeBs7zF1jqgafCWhsMR inRAscRsOYF+OltwGpsaIfjBZ0mmaZdyl1Dxahp7cHYFub+7JmSKX9peT3m8k4t3HX39 NG4Qnyd/6lg3B4Vc2W8l6Wd0WpVCxqFVYG33A= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type; b=RiU7Z7T6CEGwHApcUA3xTT02hXzZgqxxdJk7blDLQDjgPynxgwgzfukyOmVsjub7Rk qab5g6EeMIQaNDdSfWKOj4803iS/VMPKfyjCgMO+sojU56SYSgNGxjzGYhs2A9Xi+0uj fx/XgkjRo9/vzFsTgklCKl2LafwLdGvd+Mkyg= MIME-Version: 1.0 Received: by 10.231.79.136 with SMTP id p8mr5029225ibk.4.1265735421829; Tue, 09 Feb 2010 09:10:21 -0800 (PST) In-Reply-To: <20100209142658.GA38072@icarus.home.lan> References: <20100209150606.ddba52dc.gerrit@pmp.uni-hannover.de> <20100209142658.GA38072@icarus.home.lan> Date: Tue, 9 Feb 2010 09:10:21 -0800 Message-ID: From: Freddie Cash To: freebsd-stable@freebsd.org Content-Type: text/plain; charset=UTF-8 X-Content-Filtered-By: Mailman/MimeDel 2.1.5 Subject: Re: zpool vdev vs. glabel 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: Tue, 09 Feb 2010 17:10:23 -0000 On Tue, Feb 9, 2010 at 6:26 AM, Jeremy Chadwick wrote: > Also, I'm a little confused as to the use of glabel in this case. In > what condition do your disk indices (e.g. X of daX) change? Are you > yanking multiple disks out of a system at the same time and then shoving > them back into different drive bays? Are you switching between storage > subsystem drivers (ahci(4) vs. ataahci(4), for example) regularly? > > I've yet to be convinced glabel is worth bothering with, unless the > system adheres to one of the above situations (which are worthy of > strangulation anyway ;-) ). > > Use multiple disk controllers in a server, and watch as kernel updates and/or BIOS updates change the order that the controllers are probed, thus changing the dev node for every disk in the system. Use multiple disk controllers that use CAM, then move from an IDE-based CompactFlash adapter to a SATA-based CompactFlash adapter for the / filesystem, and watch the system renumber all your dev nodes. Use a RAID controller configured for JBOD or "Single Disk" arrays, and replace a drive while the server is running, which assigns the disk "largest da number +1", then renumbers everything when the server reboots. After you run into those kinds of things a few times, you'll start to use glabel(8) for everything. Plus, it just makes things easier to understand. Instead of da0 through da25 which is a mix of SATA, RAID, and USB drives, you have cfdisk0, cfdisk1, disk00 through disk24, and so on. Personally, the greatest thing to ever happen to FreeBSD is the introduction of GEOM, and the addition of the glabel class. :) While ZFS does it's own disk labelling behind the scenes, using glabel just makes things easier. -- Freddie Cash fjwcash@gmail.com