I recently made the jump from raid6 to greyhole. I'll cover why in another post, but the primary point here is that I took my array offline using the following command:
Or how to banish the ghost of raid5's past.
- mdadm -S /dev/md0 (where md0 can be whatever your raid device's name is)
Literally all I did above to recover my raid-altered drives was
- fdisk /dev/sdX
- mdadm -E /dev/sdX
You can vanquish these peskily pervasive blocks by issuing the command:
- mdadm --zero-superblock /dev/sdX
One other thing to check is that /etc/mdadm.conf is empty, as information about your raid device can reside here as well. After taking care of the superblocks and your mdadm.conf file you can be relatively sure that your array has been laid to rest for good.