From owner-freebsd-stable@FreeBSD.ORG Thu Nov 26 09:45:39 2009 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 31A011065670 for ; Thu, 26 Nov 2009 09:45:39 +0000 (UTC) (envelope-from tevans.uk@googlemail.com) Received: from mail-ew0-f226.google.com (mail-ew0-f226.google.com [209.85.219.226]) by mx1.freebsd.org (Postfix) with ESMTP id B2F958FC12 for ; Thu, 26 Nov 2009 09:45:38 +0000 (UTC) Received: by ewy26 with SMTP id 26so594898ewy.3 for ; Thu, 26 Nov 2009 01:45:37 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=googlemail.com; s=gamma; h=domainkey-signature:mime-version:received:in-reply-to:references :date:message-id:subject:from:to:cc:content-type; bh=FnTqvj3i+VlsgTlKpd3C3gJZz45CZxoBZewhwKNATPY=; b=QPxJuPlhC4MSyphLwZYSDpPKwUMlSNlxjU4Hdx2tcM+NxeYbKGkMkm90VQoW7elgwf qk+VxHJ/bfN3iMF3ykY4YoRF+UHFAMWKXkwYL5nbjlF9+w+R4UjVzuCGkvkDgPK+/YYs f2uGnvkJ7OuKBIa+frx9YTN7PuNW8KwGeBNYE= DomainKey-Signature: a=rsa-sha1; c=nofws; d=googlemail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; b=ELii0CcgjsixywM7dlWNijkQLwMkNWzWIAz75p3MhdxEHi0fXtNrZjxgfkcBkPJ25o E6pxnNO1irf57GwjvUgPuaH/fYdf+20rqn3NdlaBXt0EHmC/9W8/2g6DUcu9+ZZ82wNl pl2A+kYP4vVjTu89YD+9kB1MVAvkVHlkXE1lY= MIME-Version: 1.0 Received: by 10.213.110.17 with SMTP id l17mr9105776ebp.91.1259228737777; Thu, 26 Nov 2009 01:45:37 -0800 (PST) In-Reply-To: <20091126085034.GA51998@icarus.home.lan> References: <4B0E3ABA.3030606@tzim.net> <790a9fff0911260040i1456d7c0j4f8327d24d2966cf@mail.gmail.com> <20091126085034.GA51998@icarus.home.lan> Date: Thu, 26 Nov 2009 09:45:37 +0000 Message-ID: <2e027be00911260145q4192728cuaea1d5e6da01a1e@mail.gmail.com> From: Tom Evans To: Jeremy Chadwick Content-Type: text/plain; charset=UTF-8 X-Content-Filtered-By: Mailman/MimeDel 2.1.5 Cc: freebsd-stable@freebsd.org Subject: Re: Can't use gpt labels re-importing pool 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: Thu, 26 Nov 2009 09:45:39 -0000 On Thu, Nov 26, 2009 at 8:50 AM, Jeremy Chadwick wrote: > I'm a bit curious about something, so maybe someone can help me > understand: > > Why are people bothering with GPT labels (or in some cases, glabels) > when AHCI (whether it be ataahci.ko or ahci.ko) is in use? Under what > circumstance would the device name change dynamically in this situation? > > I've never witnessed this happening with AHCI, at least on Intel > systems, and I've hot-swapped hard disks many times over. > > My home server has 6 x ICH10 SATA ports using ahci(4), and 2 x SiL 3128 SATA ports using siis(4). When I first set it up, I created a raidz pool using MBR/BSD slices/partitions on the drives on the ahci controllers, (ie zpool create tank raidz ada[0-5]s1d). I then shutdown, connected a couple of drives to the siis controller, and booted up again. This caused the pool to fail to be imported, as the drives on siis came up as ada0 and ada1. I then wiped out the pool, and restarted the install, but this time using GPT partitioning and labelling each partition that I use. Now I can connect my drives on any interface, any order and it works correctly, always. I also get a nice label for each drive that I can scribble on the drive cage, and I can tell exactly what physical device is referred to by a label. The only cost to this was having to remember to label the drives - well worth it imo. Cheers Tom