From owner-freebsd-fs@FreeBSD.ORG Tue Jan 22 23:02:42 2013 Return-Path: Delivered-To: freebsd-fs@freebsd.org Received: from mx1.freebsd.org (mx1.FreeBSD.org [8.8.178.115]) by hub.freebsd.org (Postfix) with ESMTP id DD665205 for ; Tue, 22 Jan 2013 23:02:42 +0000 (UTC) (envelope-from fjwcash@gmail.com) Received: from mail-lb0-f171.google.com (mail-lb0-f171.google.com [209.85.217.171]) by mx1.freebsd.org (Postfix) with ESMTP id 55E37B5C for ; Tue, 22 Jan 2013 23:02:41 +0000 (UTC) Received: by mail-lb0-f171.google.com with SMTP id gg13so4210871lbb.30 for ; Tue, 22 Jan 2013 15:02:41 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:x-received:in-reply-to:references:date:message-id :subject:from:to:cc:content-type; bh=epgTUus8irZmPELv4jZRSNsBP2Tp1yUuFi2BXUzQc58=; b=MVSCtUzQKHHM38CJ6xoq2R16tB/lnYNRclkEvhRXM+i7kMTMzyWhaPdii6taMh1HxT bRxQ76B0A5/Hw3MS5miscIAH8OWyhebuQr7havoHKZGwn95RxkVcpp2UcatWhyu3IlyZ J6DTv8oZDXvbC0/gECBpFBrlZywdxoyZrMl9b6xRoy6pn+Qt/hlTpmM0LwBSyeXGs7P3 sVgSyKjrNoTKcITe0yZb3YksDNeXy0sH8/sfsKyaMpUuGtCSZj6W/OzGHJFX7UxR5ac4 PeufUQAnR/ZfE0MhgsD52wkCyOy4OE00G023xsYBqBlD0vHtNHpc8vPsX8OfE3IIbjMv nahQ== MIME-Version: 1.0 X-Received: by 10.112.44.134 with SMTP id e6mr9857851lbm.134.1358895760864; Tue, 22 Jan 2013 15:02:40 -0800 (PST) Received: by 10.114.81.40 with HTTP; Tue, 22 Jan 2013 15:02:40 -0800 (PST) Received: by 10.114.81.40 with HTTP; Tue, 22 Jan 2013 15:02:40 -0800 (PST) In-Reply-To: References: <314B600D-E8E6-4300-B60F-33D5FA5A39CF@sarenet.es> Date: Tue, 22 Jan 2013 15:02:40 -0800 Message-ID: Subject: Re: RFC: Suggesting ZFS "best practices" in FreeBSD From: Freddie Cash To: Warren Block Content-Type: text/plain; charset=UTF-8 X-Content-Filtered-By: Mailman/MimeDel 2.1.14 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 23:02:42 -0000 On Jan 22, 2013 7:04 AM, "Warren Block" wrote: > > 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? The ZFS metadata on disk allows you to move disks around in a system and still import the pool, correct. But the ZFS metadata will not help you figure out which disk, in which bay, of which drive shelf just died and needs to be replaced. That's where glabels, gpt labels, and similar come in handy. It's for the sysadmin, not the system itself.