In article <20190225050144.GA5984 at button.barrett.com.au>, Jobst Schmalenbach <jobst at barrett.com.au> wrote: > Hi. > > CENTOS 7.6.1810, fresh install - use this as a base to create/upgrade new/old machines. > > I was trying to setup two disks as a RAID1 array, using these lines > > mdadm --create --verbose /dev/md0 --level=0 --raid-devices=2 /dev/sdb1 /dev/sdc1 > mdadm --create --verbose /dev/md1 --level=0 --raid-devices=2 /dev/sdb2 /dev/sdc2 > mdadm --create --verbose /dev/md2 --level=0 --raid-devices=2 /dev/sdb3 /dev/sdc3 > > then I did a lsblk and realized that I used --level=0 instead of --level=1 (spelling mistake) > The SIZE was reported double as I created a striped set by mistake, yet I wanted the mirrored. > > Here starts my problem, I cannot get rid of the /dev/mdX no matter what I do (try to do). > > I tried to delete the MDX, I removed the disks by failing them, then removing each array md0, md1 and md2. > I also did > > dd if=/dev/zero of=/dev/sdX bs=512 seek=$(($(blockdev --getsz /dev/sdX)-1024)) count=1024 > dd if=/dev/zero of=/dev/sdX bs=512 count=1024 > mdadm --zero-superblock /dev/sdX > > Then I wiped each partition of the drives using fdisk. The superblock is a property of each partition, not just of the whole disk. So I believe you need to do: mdadm --zero-superblock /dev/sdb1 mdadm --zero-superblock /dev/sdb2 mdadm --zero-superblock /dev/sdb3 mdadm --zero-superblock /dev/sdc1 mdadm --zero-superblock /dev/sdc2 mdadm --zero-superblock /dev/sdc3 Cheers Tony -- Tony Mountifield Work: tony at softins.co.uk - http://www.softins.co.uk Play: tony at mountifield.org - http://tony.mountifield.org