Redundant boot drive setup with BTRFS and mdraid

Hello everyone! There’s a new howto by our own @phillxnet on how to setup two drives in a raid1 using mdraid and then btrfs on top for the / mirror. It’s very thorough and probably useful to every critical installation where downtime caused by a boot drive failure is unacceptable. @bkelly, you may be really interested to try it out and provide feedback.

Prior to this updated howto, we had a shorter version that stopped at mdraid and did not put btrfs over it. Instead, we went with ext4. However, this required a special exception to allow ext4 on /. With this new approach, we eliminate that special case and be consistent with the requirement of having btrfs on /.

If you read the howto, you’ll see that it’s very very thorough. Thanks for a great contribution @phillxnet!