mdadm won't boot in Ubuntu/Mint/Debian anymore.
You just get the following in a loop:
mdadm: CREATE group disk not found
Incrementally started RAID arrays.
Incrementally starting RAID arrays...
mdadm: CREATE group disk not found
Incrementally started RAID arrays.
Incrementally starting RAID arrays...
mdadm: CREATE group disk not found
Incrementally started RAID arrays.
Incrementally starting RAID arrays...
mdadm: CREATE group dis........