From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from lists.gentoo.org (pigeon.gentoo.org [208.92.234.80]) by finch.gentoo.org (Postfix) with ESMTP id 51051138C9D for ; Wed, 29 Apr 2015 06:13:52 +0000 (UTC) Received: from pigeon.gentoo.org (localhost [127.0.0.1]) by pigeon.gentoo.org (Postfix) with SMTP id 732CBE097B; Wed, 29 Apr 2015 06:13:46 +0000 (UTC) Received: from mail-wi0-f181.google.com (mail-wi0-f181.google.com [209.85.212.181]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by pigeon.gentoo.org (Postfix) with ESMTPS id 4B6E7E08EE for ; Wed, 29 Apr 2015 06:13:45 +0000 (UTC) Received: by wief7 with SMTP id f7so32317203wie.0 for ; Tue, 28 Apr 2015 23:13:44 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=message-id:date:from:user-agent:mime-version:to:subject:references :in-reply-to:content-type:content-transfer-encoding; bh=tn/Tjwt+ng93yheyRG2NgmRmlcNKM0MAGtjyNI9BRl0=; b=waXmUoUCgu4B15fPbLnJbn7GbE68+GpkjCxGe3KIj6NZJiMgPbpUKgMXHXru9Eo/iL RaATbbnsshYJvznxl6/DjsedhOERTLeya463K9yBrP3Uxa1NxgGqNRIQ8ZIM+UWkmHx2 5NakMTNORVrMkOxUwDXYwuLAv7hIOhKgdmRPkMVGnU80O5NHm2NXluQyoEbt9nIyCkj5 Dg0p0FM5ete5aGft44yn/trkD6JE+j0WZFYdUJVYAzlX7fYq2+w0Iqv21Jus4/5Yowig k84ilSLikMf03Tp1kW0gp12feaRhcB4KrEAvxDdLFP+iz/+qH2mlMjkFaXBMQlSDsjXj Op/w== X-Received: by 10.180.84.67 with SMTP id w3mr2797900wiy.68.1430288024126; Tue, 28 Apr 2015 23:13:44 -0700 (PDT) Received: from [172.20.0.41] (105-237-204-233.access.mtnbusiness.co.za. [105.237.204.233]) by mx.google.com with ESMTPSA id pm1sm19133789wjb.23.2015.04.28.23.13.42 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 28 Apr 2015 23:13:43 -0700 (PDT) Message-ID: <55407695.7000808@gmail.com> Date: Wed, 29 Apr 2015 08:13:41 +0200 From: Alan McKinnon User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.6.0 Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-Id: Gentoo Linux mail X-BeenThere: gentoo-user@lists.gentoo.org Reply-to: gentoo-user@lists.gentoo.org MIME-Version: 1.0 To: gentoo-user@lists.gentoo.org Subject: Re: [gentoo-user] Hard drive storage questions References: <553F474E.4040101@gmail.com> <553FA0DD.1090101@gmail.com> <20150428162448.160e1683@digimed.co.uk> In-Reply-To: <20150428162448.160e1683@digimed.co.uk> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit X-Archives-Salt: 4bf8a10e-4bef-4cbe-9a13-e1937e9116fd X-Archives-Hash: 2d6790aa06367a87a703bb2a9baece4a On 28/04/2015 17:24, Neil Bothwick wrote: > On Tue, 28 Apr 2015 17:01:49 +0200, Alan McKinnon wrote: > >> When you use only LVM for this and nothing else, you have a high risk of >> losing everything if one disk fails. Why? Because LVM decides itself >> which extent it will put data on. Maybe a whole file is on one disk, >> maybe it's spread across two, because the software is designed so that >> you don't have to be concerned with that. The only thing that LVM does >> is expand your storage space as a single volume and make it easier to >> shuffle things around without having to backup/repartition/restore. > > An alternative is to create a new volume group on the new disk and mounts > PVs at various points in your home directory. That way you get the extra > space and much of the flexibility without the risk of a failure on a > single drive taking out data on both. However, if you are concerned about > data loss, you should be using RAID t a minimum, preferably with an error > detecting filesystem. I've used that scheme myself in the past. You do get the increased space but you don't get much in the way of flexibility. And it get COMPLICATED really quickly. To get around the situation of one drive almost full and the other having lots of space, folks often use symlinked directories, which you forget about and no-one else can figure out what you did... It all smacks of the old saw: For any non-trivial problem, there is always at least one solution that is simple, elegant, and wrong. -- Alan McKinnon alan.mckinnon@gmail.com