Convert RAID1 to single disk

[KendyfortheState]

I have an 8-year-old server running Red Hat (I think version 7) that I have successfully cloned and run as a VirtualBox guest on an Ubuntu host. The only problem I have is that it was originally set up on a software RAID array, and now when it boots up in VirtualBox it complains that the array is degraded. I suppose as long as it runs ok it doesn't really matter, but I'd be interested to know if there is any way to convert the broken mirror back to a single disk. I've looked at all kinds of tutorials that explain how to convert a single-disk system to RAID, but can't find any that describe what I want to do.

[dancho]

I think that you can get rid of the RAID like this. Boot from a LiveCD of some sort (say Ubuntu 10.04). Let's say the drive that the mirror lives on is /dev/sda. Then in a terminal:

sudo apt-get update
sudo apt-get install mdadm
sudo modprobe md_mod
sudo modprobe raid1
sudo modprobe raid10 # In case you have RAID10 instead of RAID1

mdadm --zero-superblock /dev/sda # Destroys the md superblock

# Let's say your root partition is /dev/sda1. If not, replace sda1 with whatever it is.

mount /dev/sda1 /mnt

# If you have separate /boot, /usr/, and /var, mount them at this point, e.g.:

mount /dev/sda5 /mnt/usr # and similarly for the others.

chroot /mnt
rm /etc/mdadm/mdadm.conf
mount -t proc none /proc
mount -t sysfs none /sys
mount -t devtmpfs none /dev

grub-mkconfig > /boot/grub/grub.cfg
grub-install --recheck /dev/sda

# Now, edit your /etc/fstab, and make sure that there are no references to /dev/md devices, i.e. that all entries are either /dev/sdaN or UUID=XXXXXXXXXXXXXXXX


Now, reboot, and make sure the system is trying to boot from the drive you were just working on (in this case /dev/sda).

If you ever change your mind, you can use my guide to re-convert your system to a mirrored drive setup:

http://www.blogger.com/adsense-overview ... 6694337445

[areys1]

Has this been tested with any success?

[Sasquatch]

Should work. But I wonder what this has to do with VB. This situation can easily be done on a physical system, therefore I'm locking this one.