Raid 1 is useful but not the best solution.
The point is everytime the same... people confuse HA with DR. Raid 1 provide a COPY of disk, so you can access your disk (even if one is failed), but this doesn't mean you can keep working without problems.
One your system is up and running, I usually take a full backup for the entire system. Then, day per day, a normal backup. In case of a disaster, you can rebuild your array (as described in previous post) from the image.
I know this is disappointing, That's because I rely on RAID5 instead of RAID1 (which actually is the same process of raid one in some way, but it can rebuild everything from just 2 disks, there's no principal disk).