From mboxrd@z Thu Jan 1 00:00:00 1970 From: Brian Candler Subject: Re: Using mdadm instead of dmraid for BIOS-RAID root volume Date: Fri, 11 Oct 2013 14:03:02 +0100 Message-ID: <5257F706.8050708@pobox.com> References: <5253F7C2.2030401@pobox.com> <52541473.4020005@pobox.com> <52545092.1040001@arcor.de> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <52545092.1040001@arcor.de> Sender: linux-raid-owner@vger.kernel.org To: Martin Wilck Cc: linux-raid@vger.kernel.org List-Id: linux-raid.ids On 08/10/2013 19:36, Martin Wilck wrote: > On 10/08/2013 04:19 PM, Brian Candler wrote: >> > Anyway, I'm not so worried about having broken this machine, as it >> needed a reinstall anyway, but I do wonder what would have been the >> correct way to get mdraid instead of dmraid at boot time for this root >> volume? >> >> After some more searching, it looks like the udev rules were nobbled to >> disable this in >> https://bugs.launchpad.net/ubuntu/+source/mdadm/+bug/1030292 >> >> A possible way to re-enable is here: >> https://bugs.launchpad.net/ubuntu/+source/mdadm/+bug/1054948/comments/9 >> >> I'm a bit concerned about the issues around clean shutdown, and hence >> whether is really production-ready yet. > In general, this works. I have seen it work with CentOS, Fedora, and > various SUSE distributions. FWIW, I found problems on stock CentOS 6.4. I had created two RAID volumes within the BIOS: "BOOT" (4GB) "LVM" (rest of disk) These are correctly detected and come up as md0 (container), md125 (BOOT), md126 (LVM). In a previous install using Debian I had set these up as ext4 and LVM respectively. In the CentOS graphical installer, they are shown as: V Hard Drives md125 4096 ext4 md126 902246 vg Physical volume (LVM) (md0 is not shown) Problem: if I double-click on md125, or select md125 and click Edit..., nothing happens. Therefore I cannot mark it as being used for the /boot filesystem. However, if I double-click on md126, it correctly pops up "You cannot edit this drive: This device is part of the LVM volume group 'vg'." Then if I delete all the logical volumes, and the volume group, I expected to be able to edit md126 - but I can't. Again, just nothing happens when I double-click on it. I can neither partition it, nor change it to ext4 and mount it. So it looks like there's work remaining to make this usable in CentOS too. Regards, Brian.