Convert RAID superblock from 0.9 to 1.0

1 08 2017

The kernel wiki have a section with some documentation about this process, but it’s a bit outdated. If you have mdadm-3.3 or newer (usually yes), is it possible to change the superblock in two steps. First get the devices information:

mdadm --detail /dev/md0

And do it:

mdadm --stop /dev/md0
mdadm --assemble /dev/md0 --update=metadata ...list.of.devices...

http://www.spinics.net/lists/raid/msg48367.html
https://raid.wiki.kernel.org/index.php/RAID_superblock_formats