From mboxrd@z Thu Jan 1 00:00:00 1970 From: Martin Wilck Subject: Re: Using mdadm instead of dmraid for BIOS-RAID root volume Date: Tue, 08 Oct 2013 20:36:02 +0200 Message-ID: <52545092.1040001@arcor.de> References: <5253F7C2.2030401@pobox.com> <52541473.4020005@pobox.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <52541473.4020005@pobox.com> Sender: linux-raid-owner@vger.kernel.org To: Brian Candler Cc: linux-raid@vger.kernel.org List-Id: linux-raid.ids 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. It may require some work on Ubuntu's side. 1 The udev rules for incremental mdadm autoassembly need to be in place. The upstream rules should be fine. They can normally coexist with the rules for dmraid. 2 For shutdown, the distro must take care not to kill mdmon before file systems are unmounted, and to run mdadm --wait-clean after any write access to file systems is finished. Martin