I am extremely disappointed to find that the most basic raid 1 maintenance functions remain missing since 2014. I’m talking about expanding storage capacity on the device. My mirror is 2tb raid 1. One disk died. I am unable to replace it with a 6tb (I found posts suggesting this could be done. Not on my device) and the device is stuck “expanding”. Putting in a 2tb replacement does not get it unstuck. Only solution offered by WD will lose the drive contents.
You could refer to the following link: https://support-en.wd.com/app/answers/detail/a_id/27421