mdadm does not seem to support growing an array from level 1 to level 10.
I have two disks in RAID 1. I want to add two new disks and convert the array to a four disk RAID 10 array.
My current strategy:
- Make good backup.
- Create a degraded 4 disk RAID 10 array with two missing disks.
- rsync the RAID 1 array with the RAID 10 array.
removeone disk from the RAID 1 array.
- Add the available disk to the RAID 10 array and wait for resynch to complete.
- Destroy the RAID 1 array and add the last disk to the RAID 10 array.
The problem is the lack of redundancy at step 5.
Is there a better way?