Because one of the WD Blue disks in the backup RAID1, /dev/md0, failed I bought a pair of WD Red NASdrives. They're installed and partitioned as a linux filesystem. They show up in fdisk -l as /dev/sde/ and /dev/sdf/.
When I try to create a new RAID1 on these disks I get this result: # mdadm --create --verbose /dev/md0 -l 1 -n 2 /dev/sd{e,f} mdadm: /dev/sde appears to be part of a raid array: level=raid0 devices=0 ctime=Wed Dec 31 16:00:00 1969 mdadm: partition table exists on /dev/sde but will be lost or meaningless after creating array mdadm: Note: this array has metadata at the start and may not be suitable as a boot device. If you plan to store '/boot' on this device please ensure that your boot-loader understands md/v1.x metadata, or use --metadata=0.90 mdadm: /dev/sdf appears to be part of a raid array: level=raid0 devices=0 ctime=Wed Dec 31 16:00:00 1969 mdadm: partition table exists on /dev/sdf but will be lost or meaningless after creating array mdadm: size set to 1953383488K mdadm: automatically enabling write-intent bitmap on large array Continue creating array? yes mdadm: /dev/md0 is already in use. I deleted /dev/md0, but mdadm still sees it being present. As I need only one RAID how can I get mdadm to create a new /dev/md0 because it's not in /dev/. Rich