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 ECBC7138CD3 for ; Thu, 28 May 2015 23:51:32 +0000 (UTC) Received: from pigeon.gentoo.org (localhost [127.0.0.1]) by pigeon.gentoo.org (Postfix) with SMTP id EC267E08B0; Thu, 28 May 2015 23:51:25 +0000 (UTC) Received: from mail-ie0-f172.google.com (mail-ie0-f172.google.com [209.85.223.172]) (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 DF22FE0899 for ; Thu, 28 May 2015 23:51:24 +0000 (UTC) Received: by ieczm2 with SMTP id zm2so50739580iec.1 for ; Thu, 28 May 2015 16:51:24 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:sender:in-reply-to:references:date:message-id:subject :from:to:content-type; bh=S66iC15tA2Bkic3dUDzJZq7DY6ZtjW/85joObj6Jmf0=; b=cLkOqSca47Wr1qi82YJyT9v9hKp64+TL9do5nyV+DTxqiOg8NhE84EA7GwtnqAV+/1 cratIts84Ccbkfkbi8Gp5ztUOh7f7gP5GPAoVLJ9Vs9lwk8Qgc3eXP8D8NUFuXRmUPYo 8tNeWQOgikeFkhXSFdGt9OHyUFqVPT/yauMrMGfEkO8MZYuvySOu40c6rY69ZQVbhWuU NfzX/h5fJYtgybQHqMstkc3Tkas6M3qt0QLr34392uO2/aaxJFxPPqrhg3rmaFhutDoG DcZiOW7GEJsm8eNpUxguMSA+xoMjbPasQiwpY78QywSvOg508t936ELcwINQViBcGCX1 RaEQ== 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 X-Received: by 10.50.102.68 with SMTP id fm4mr560015igb.25.1432857084283; Thu, 28 May 2015 16:51:24 -0700 (PDT) Sender: freemanrich@gmail.com Received: by 10.107.6.34 with HTTP; Thu, 28 May 2015 16:51:24 -0700 (PDT) In-Reply-To: <1792747.JZnWCiL56h@wstn> References: <2988031.1MpZN5Nf01@wstn> <4877493.0ZaXbKOvBr@wstn> <1792747.JZnWCiL56h@wstn> Date: Thu, 28 May 2015 19:51:24 -0400 X-Google-Sender-Auth: GBxE9ADIiOjmcI6RmZJagZIHNso Message-ID: Subject: Re: [gentoo-user] General weirdness - a tale of woe. From: Rich Freeman To: gentoo-user@lists.gentoo.org Content-Type: text/plain; charset=UTF-8 X-Archives-Salt: c991fe25-99c2-402d-b731-94cbf3b012b2 X-Archives-Hash: 21efe528f6c8998370b3b92749d20fc8 On Thu, May 28, 2015 at 1:03 PM, Peter Humphrey wrote: > On Thursday 28 May 2015 15:36:04 I wrote: >> On Thursday 28 May 2015 08:44:27 Rich Freeman wrote: >> > With an approach like yours, mdadm will attempt to create md1 by >> > looking ONLY at sda1 and sdb1, and if that pair forms a valid array it >> > is started, and if not it is not. If you add a new drive to your >> > system or for whatever reason the kernel/udev rules change a little or >> > some race condition changes a little then your devices might get >> > different names, and the array will not be assembled. >> >> Hmm. I wonder if that's what's happening to me. Perhaps I'd better adopt >> UUIDs then, once I work out what mine are. Thanks for the advice. > > I've found blkid, which tells me the UUIDs of my various devices, thus: > > # blkid /dev/md7 > /dev/md7: UUID="ycGMf9-hEP2-tjT4-AtkJ-n8RI-pZ44-RqvlEY" > TYPE="LVM2_member" Just keep in mind that the UUID that goes into mdadm.conf might not be the same UUID returned by blkid. I'm honestly not certain either way. You can get the mdadm ID from mdadm --detail --scan. > > Two odd things: > 1. /dev/md7 is the physical volume in which logical volumes are defined, > so I'm surprised to see TYPE="LVM2_member". I'm pretty sure this is fine. It recognizes it as an LVM pv, so that makes it an LVM2 member. > 2. There is no entry corresponding to /dev/md7 under /dev/disk/by-uuid, > though /dev/md1 and /dev/md5 do have entries there [1]. udev may be configured to not create uuid symlinks for LVM pvs (since you wouldn't directly mount them anyway). The others contain filesystems and do get symlinks. > > What should I be doing about this? I'd probably just edit your mdadm.conf to be more liberal with scanning, and add the arrays output by mdadm --detail --scan to your config file. That alone may make your problems go away, and it should be pretty harmless. > > I assume that the ../../dm-N links refer to the LVs - there are 15 of them. > md7 is conspicuous by its absence. This seems like a problem to me, and it > may account for /dev/md7 sometimes not being started at boot time. > LVM is just a wrapper around DM, so that is normal. Nothing about what you've written here concerns me. -- Rich