From mboxrd@z Thu Jan 1 00:00:00 1970 From: Maxime Boissonneault Subject: Re: Upgrading a software RAID Date: Sat, 30 May 2009 14:11:52 -0400 Message-ID: <4A2176E8.9090701@usherbrooke.ca> References: <20090528141457.GA30322@cthulhu.home.robinhill.me.uk> <4A1EA095.9090406@usherbrooke.ca> <20090528150849.GB30322@cthulhu.home.robinhill.me.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20090528150849.GB30322@cthulhu.home.robinhill.me.uk> Sender: linux-raid-owner@vger.kernel.org To: linux-raid@vger.kernel.org List-Id: linux-raid.ids >> If the / was on a RAID5, would it be able to boot with 2 disks ? >> If so, is it possible to convert my RAID0 to a RAID5 ? >> For example, I could boot on a CD, backup / onto /home, delete the RAID0 >> array and recreate it as RAID5, then restore the backup. Would this work ? >> >> > Yes, a RAID-5 will run fine with just two disks. You could certainly > boot from CD, backup, recreate the RAID, then restore - you'd probably > need to update the mdadm.conf file (and the initrd) to indicate the new > array UUID and details though. > > You may also want to read through the GRUB section on > http://en.gentoo-wiki.com/wiki/RAID/Software to see how to install grub > onto all the drives (avoiding the issue of which drive is currently > being booted from). > > Ok. This is the configuration I had : /dev/md1 was a RAID0 composed of /dev/sda2, /dev/sdb2 and /dev/sdc2 I did this : mdadm --stop /dev/md1 mdadm --zero-superblock /dev/sda2 mdadm --zero-superblock /dev/sdb2 mdadm --zero-superblock /dev/sdc2 and then this : mdadm --create --verbose /dev/md1 --level=5 --raid-devices=3 /dev/sda2 /dev/sdb2 /dev/sdc2 I used the rescue mode from an alternate CD (hardy 8.04.2) to format /dev/md1 as ext3. Then, I restored the backup and updated the /etc/mdadm/mdadm.conf file with the output of mdadm --detail --scan. Now, GRUB loads (it was on /dev/md0 which is a RAID1 composed of sd*1), and it tries to load Ubuntu, but it just won't load. You said that I would have to edit initrd... what is that and what do I have to change in it ? Thanks, Maxime Boissonneault