Thanks a lot to you 3 for your thoughts. RAID1 on the overlapping capacity: I don't like that idea much because RAID1 has an extra cost where any modification on disk1 will be performed on disk2. I want to reap the benefits of having disk1 for the OS and disk2 for data. That makes the overall system much faster, because each drive is ddicated to 1 task, and each task is independent.
@Crystal, thanks a lot for all the details. I am not planning to share the home drive, because indeed I feared the extra complications. the extra partition m is beyond the OS partitions. Your point regarding no guarantee for the system to boot to disk 2 is well taken. It makes me question if it's worth doing at all. Do yo uhave a sense if there is a large enough probability of disk1 failing catastrophically enough for the UEFI to directly boot to disk2, rather than being in a bad state on disk1? Thanks!
