I'm using a pi 4 to replace my pi 3B+ as my Octoprint server. To protect my gcode files I'm using 2 usb drives mirrored with mdadm to hold the code. When I boot the pi it hangs and I have to unplug the usb drives to boot it again, it hangs again when it tries to mount the mirror but plugging the usb drives back in allows it to mount the mirror and finish booting.
What might I be missing here? When I formated the drives I gave them a Linux partition label, so it shouldn't be trying to mount them as /boot.