Best way to grow Linux software RAID 1 to RAID 10

Posted by Hans Malherbe on Server Fault See other posts from Server Fault or by Hans Malherbe
Published on 2009-07-21T18:20:07Z Indexed on 2012/04/07 17:33 UTC
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Filed under:

linux

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software-raid

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mdadm

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.
fail and remove one 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?

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