A few steps to dismantling a Linux software RAID array.
I’ve obviously been playing around with software RAID on Linux. Sometimes you have to do something several times before finally getting it right.
Volume groups that have been overlaid onto a RAID array need to be removed first.
Note: Remember, when making changes to disk configurations: if there’s any doubt, reboot.
1. Check all devices.
2. Check the raid disk.
mdadm --detail /dev/md0
3. Unmount the raid device.
umount -l /dev/md0
4. Stop the raid device
mdadm --stop /dev/md0
5. Zero the superblocks on each raid volume.
mdadm --zero-superblock /dev/sdb ...
6. Remove the raid device.
mdadm --remove /dev/md0
7. Remove relevant lines from /etc/fstab.