Re: Upgrading a software RAID
From: Bill Davidsen <hidden>
Date: 2009-06-02 18:23:49
Maxime Boissonneault wrote:
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The initrd is the ramdisk which the kernel boots to first, containing the various modules and utility programs (like mdadm) needed to access the main root filesytem. A quick search suggests that you need to run 'update-initramfs -u' on Ubuntu. You'll need to boot off the CD and chroot onto the new array first though - something like: - Boot off CD - Assemble the RAID arrays - Create a mount point for the new array (mkdir /mnt/newroot) - Mount the root filesystem (mount /dev/md1 /mnt/newroot) - Mount the proc filesystem (mount -o bind /proc /mnt/newroot/proc) - Mount the sys filesystem (mount -o bind /sys /mnt/newroot/sys) - Mount the dev filesystem (mount -o bind /dev /mnt/newroot/dev) - Chroot to the new array (chroot /mnt/newroot /bin/bash) - Mount the boot filesystem (mount /boot) - Update the initramfs (update-initramfs -u) - Unmount the boot filesystem (umount /boot) - Exit the chroot (exit) - Unmount the dev filesystem (umount /mnt/newroot/dev) - Unmount the sys filesystem (umount /mnt/newroot/sys) - Unmount the proc filesystem (umount /mnt/newroot/proc) - Unmount the root filesystem (umount /mnt/newroot) - Reboot That's just from memory though, so watch out for any warnings/errors. The other issue you _may_ have is the raid5 module missing from the initrd - you'd best check that raid5 is listed in /etc/initramfs/modules.RAID5 should not be missing, my /home was a RAID5.Yes, but /home is only mounted after it's accessed the root partition. It can then read any modules from the root partition, so the raid5 module could still be missing from the initrd. I suspect it'll have included it though.I did as you suggested above. I still get the same error message. I have looked and did not find /etc/initramfs/modules. Instead, I found /etc/initramfs-tools/modules. In this file, there were a couple of comment lines explaining how to enable modules. No modules were included. I uncommented the "raid1" and added "raid5" and ran the procedure again. Still getting the same problem. Since the problem seems to be the boot, I will try to do a fresh install, then restore my backup while keeping the /boot from the fresh install.
If this were Fedora I would be using mkinitrd to get the right modules in the boot image, however Ubuntu requires another method, which I don't know well enough to describe. You are probably on the right tract though, getting the modules and mdadm.conf available at boot. -- Bill Davidsen [off-list ref] Even technical things can appear to be magic, if the documentation is obscure enough. For example, PulseAudio is configured by dancing naked around a fire at midnight, shaking a rattle with one hand and a LISP manual with the other, while reciting the GNU manifesto in hexadecimal.