On 24 April 2015 at 12:54, Toby Corkindale <toby@dryft.net> wrote:
I think people were suggesting blanking each removed half of the array, prior to making the underlying block device encrypted, then adding and re-mirroring.

Wait, you're suggesting encrypting each drive separately, and then adding the result to a linux RAID device?

That's.... crazy, but it might even work.

Would be interesting to see what happens to performance considering you have to do a different encryption operation per drive of the RAID array.

Unfortunately it looks like it's impossible to convert an existing single drive to a RAID drive.. Or at least the instructions here do the good old copy from one to the other dance.

https://wiki.archlinux.org/index.php/Convert_a_single_drive_system_to_RAID

I suppose you could in theory do this for systems that are already RAID 1 though.. (as Russell suggests)