From owner-freebsd-stable@FreeBSD.ORG Fri Jan 25 19:58:20 2013 Return-Path: Delivered-To: freebsd-stable@freebsd.org Received: from mx1.freebsd.org (mx1.FreeBSD.org [8.8.178.115]) by hub.freebsd.org (Postfix) with ESMTP id 39F48663 for ; Fri, 25 Jan 2013 19:58:20 +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 F1E36665 for ; Fri, 25 Jan 2013 19:58:19 +0000 (UTC) Received: from wonkity.com (localhost [127.0.0.1]) by wonkity.com (8.14.6/8.14.6) with ESMTP id r0PJwF93005642; Fri, 25 Jan 2013 12:58:15 -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 r0PJwFp9005639; Fri, 25 Jan 2013 12:58:15 -0700 (MST) (envelope-from wblock@wonkity.com) Date: Fri, 25 Jan 2013 12:58:15 -0700 (MST) From: Warren Block To: Jeremy Chadwick Subject: Re: RFC: Suggesting ZFS "best practices" in FreeBSD In-Reply-To: <20130124174039.GA35811@icarus.home.lan> Message-ID: References: <20130124174039.GA35811@icarus.home.lan> 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]); Fri, 25 Jan 2013 12:58:15 -0700 (MST) Cc: freebsd@deman.com, freebsd-stable@freebsd.org X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 25 Jan 2013 19:58:20 -0000 On Thu, 24 Jan 2013, Jeremy Chadwick wrote: >>> #1. Map the physical drive slots to how they show up in FBSD so if a >>> disk is removed and the machine is rebooted all the disks after that >>> removed one do not have an 'off by one error'. i.e. if you have >>> ada0-ada14 and remove ada8 then reboot - normally FBSD skips that >>> missing ada8 drive and the next drive (that used to be ada9) is now >>> called ada8 and so on... >> >> How do you do that? If I'm in that situation, I think I could find the >> bad drive, or at least the good ones, with diskinfo and the drive serial >> number. One suggestion I saw somewhere was to use disk serial numbers >> for label values. > > The term FreeBSD uses for this is called "wiring down" or "wired down", > and is documented in CAM(4). It's come up repeatedly over the years but > for whatever reason people overlook it or can't find it. I was aware of it, it just seems like there ought to be a better way to identify drives than by messing with the hardware configuration. Something more elegant, less tied to changing the hardware configuration of the host. Assigning the drive serial number as a label, for example.