Dual Root setup

I know there's lots of info available about dual boot - but not much I could find on Dual Root. What is Dual Root? This is a machine with 2 "root" disks where the second one is a hot standby - in event of root disk failure the second disk can be booted very quickly. This makes recovering very fast and thereafter replacing the bad drive and rebuilding very straightforward. And no new install needed! I have now set this up on a few machines and its working well - so I wrote up some notes and am sharing them in case others who may be interested in doing something similar might find them useful. My notes explaining how to do this are available here: https://github.com/gene-git/blog best gene