I am trying to set up a simple mirror between 2 identical (same size and model) new 500G external hard drives. Each time I try to create the RAID I receive the following error. My linux skills are fairly limited so this error may be simpler to figure out than my interpretation. I can say that disk will not contain the boot loader since I am using a raspberry pi 3 and booting from the latest OMV 4 image.
Any clarification, and testing steps I can take from here would be appreciated. The snap of the error is attached.