RAID 1 (mirroring) clarifications

Can anyone clarify what VyOS (either 1.1.7 or -current) does when configuring raid on a system with multiple disks?

Does VyOS write grub to both disks so that the system would still be able to boot in the event a disk is lost? If not- can/should that be done after the fact?

As much as I prefer the simplicity of mdadm- am I better off using the onboard Intel raid option rom (as I believe that will still allow me to boot with a failed drive)?

Never checked that, but suppose that it should write to both
it can be checked in virtualbox or vmware

I plan on using th built in Intel Raid, but without the driver or software it will be hard to know if there is a failure other than when booting up.

OK I could never get the Intel Raid to work with VyOS on bare metal. So I read up and learned how to to mdadm raid 1. Pretty click. I have mirrored just the partition for VyOS so that I have options when it comes to replacing a failed drive down the road.