From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from pigeon.gentoo.org ([208.92.234.80] helo=lists.gentoo.org) by finch.gentoo.org with esmtp (Exim 4.60) (envelope-from ) id 1RikTn-0005Fy-El for garchives@archives.gentoo.org; Thu, 05 Jan 2012 10:23:27 +0000 Received: from pigeon.gentoo.org (localhost [127.0.0.1]) by pigeon.gentoo.org (Postfix) with SMTP id BDFCF21C102; Thu, 5 Jan 2012 10:23:13 +0000 (UTC) Received: from mail-we0-f181.google.com (mail-we0-f181.google.com [74.125.82.181]) by pigeon.gentoo.org (Postfix) with ESMTP id D555821C02B for ; Thu, 5 Jan 2012 10:22:15 +0000 (UTC) Received: by werm12 with SMTP id m12so283423wer.40 for ; Thu, 05 Jan 2012 02:22:15 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=googlemail.com; s=gamma; h=from:to:subject:date:message-id:user-agent:in-reply-to:references :mime-version:content-transfer-encoding:content-type; bh=hQxMit8VThxMKP6v3bhz3NDynYPC+B2HKSyuqmEV1N4=; b=UuSwns/skKUv/TzEq+5USIDzWrlZS0/bwFxhwhXc76+iv8JRtO0fBmQe7ZOpsFlHAA HHMMS7n2nqni4NHEfGTD9SFi3WFK90yKfctZcs7EHZj2atbnUVonc/qVIvnARWDJdkNo w06EZehiKQJCFlddkW1Lu1os/47VwLY3p5ZIw= Received: by 10.216.139.156 with SMTP id c28mr904986wej.34.1325758935009; Thu, 05 Jan 2012 02:22:15 -0800 (PST) Received: from localhost.localnet (p4FC60E45.dip0.t-ipconnect.de. [79.198.14.69]) by mx.google.com with ESMTPS id h3sm3954743wia.8.2012.01.05.02.22.12 (version=TLSv1/SSLv3 cipher=OTHER); Thu, 05 Jan 2012 02:22:13 -0800 (PST) From: Volker Armin Hemmann To: gentoo-user@lists.gentoo.org Subject: Re: [gentoo-user] How to get raid Date: Thu, 05 Jan 2012 11:22:10 +0100 Message-ID: <1581658.zyO2e55q4a@localhost> User-Agent: KMail/4.8 rc1 (Linux/3.0.7; KDE/4.7.4; x86_64; ; ) In-Reply-To: <1325735145.22553.17.camel@laptop.limeyworld> References: <1325645839.4553.13.camel@laptop.limeyworld> <2784979.6pH95vXhbC@localhost> <1325735145.22553.17.camel@laptop.limeyworld> 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 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" X-Archives-Salt: 39be8b15-1cd2-4f74-968d-4bda4721a840 X-Archives-Hash: 801fd6f49b6f95f9fcb16dcc39a9a742 Am Mittwoch, 4. Januar 2012, 22:45:45 schrieb Jeff Cranmer: > On Thu, 2012-01-05 at 04:01 +0100, Volker Armin Hemmann wrote: > > the short one: > > > > partition one disk with (c)fdisk. Use sfdisk to transfer the partition > > scheme to the other disks. > > > > run mdadm --create /dev/md0 level=whatever you want --raid- > > devices=thenumberofdevices /dev/sdXY /dev/sdZY ... > > > > mdadm --detail --scan >> /etc/mdadm.conf > > > > done > > OK, but there is active data on the disks, so I don't want to partition > them. They should already partitioned, and running fdisk will erase the > data. first rule: always mount a scratch monkey In your case: always backup data. There is a way to preserve the data on one disk, create a raid5 with one disk missing, then copying the data onto the raid and add the disk. But that is high risk stuff. > > If I run mdadm --create /dev/md0 level=5 > --raid-devices=3 /dev/sdb /dev/sdc /dev/sdd, will that erase data > already on the disks? > > Prior to running this command, there is no /dev/md entry. Is this > correct? yes. You might have to create the nodes with mknod - my memory is sketchy there. > Looking further by using fdisk, it appears that sdc has a linux > partition on sdc1 starting at sector 34, and a GPT partition of size 0+ > at /dev/sdc4, sector 0. Nothing else is on that disk (no sdc2 or sdc3). > > sdd and sdb report invalid partition table flags and do not appear to > have active partitions. Does this make sense? if you used fakeraid before, yes. But that means: without the original fakeraid everything on that disks is inaccessible... and you need to partition them. > > Is it possible that I ordered the disks incorrectly when I installed > them, and by simply swapping disks b and c at the raid I can get things > to start making sense? Is there an order to a set of RAID5 disks? I > thought any two of three RAID5 disks could be recovered, regardless of > which one dies? no. First, the order of the disks is irrelevant, but the most important thing: with Raid5 ONE disk out of an array might fail. No matter how many disks - two fail and everything is lost. > > > there is a reason why I never ever touch genkernel. > > > > you should forget that crap. You don't need to copy around anything. If > > your root is not on some fancy setup, you don't need initramfs. > > > > Just make a nice kernel, put it in /boot. Done. > > OK. The OS disk is non-RAID (120GB SSD), so I don't need any fancy > options in my kernel. All the domdadm and dodmraid stuff is needed just > when your OS disk is raided. Correct? yes -- #163933