When trying to follow the procedure as per Red Hat documentation, the below command is failing:   

$ mdadm -CR /dev/md/dummy -l0 -n2 /dev/imsm0 -z10M --assume-clean 
mdadm: You haven't given enough devices (real or missing) to create this array

As it seems that the path to the imsm0 device is wrong, and command should be:

$ mdadm -CR /dev/md/dummy -l0 -n2 /dev/md/imsm0 -z10M --assume-clean 

need to correct our relevant documentation. Also, it would be good to verify if there is a need to update the procedure.

Doc: https://docs.openshift.com/container-platform/4.18/installing/install_config/installing-customizing.html#installation-special-config-raid-intel-vroc_installing-customizing

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