Current documentation doesn't mention supporting disk mirroring during OCP installation with the IPI method, even if this should be supportable already.

currently "Mirroring is available only for user-provisioned infrastructure deployments on RHCOS systems."

as per NOTE in documentation:

https://docs.openshift.com/container-platform/4.10/installing/install_config/installing-customizing.html#installation-special-config-mirrored-disk_installing-customizing