Am 04.05.20 um 12:48 schrieb Stefanie Leisestreichler:

Hi.
I have a running RAID 1 based on /dev/sda1 and /dev/sda2 with
metadata=1.2 with mdadm version 3.2.5.

I took an image of /dev/sda using dd.
There is a computer with identical hardware (test-env) where I put in
this image. When I start this computer, it is booting and recognizing
the raid active as md0 with state [2/1] [U_] like expected.

My target is to restore the raid using another new and blank hard disk
in the test-env computer. I know I have to format the new disk
identically to the format the image is providing, but I am unsure about
how to add the new disk to the raid array.

Could you please guide me?

mdadm /dev/mdX --add /dev/sdx{1,2}