When you only have a master and backup drive, in the case of failure, you put yourself in a critically dangerous position. Restoring from backup isn't just str

When you only have a master and backup drive, in the case of failure, you put yourself in a critically dangerous position. Restoring from backup isn't just stressful for the human, it's also stressful for the hardware. When you have a single failure, it's nice to at least have TWO independent backups in case during the restore there is a second failure (either due to hardware or operator).