That's why I like RAID 1 mirror sets: The system performs the backup in real time, and your data always exists on two drives.

I can relate to being nervous about making a mirror. When I rebuilt the server recently, I had all my existing data on one single terabyte drive, and none of the documentation I could find could reassure me that the data wouldn't be erased in the course of adding another blank drive to create the mirror set. So I dithered a couple of weeks, operating on just the single drive, until I finally decided to just say F-it, and bought two more $70 terabyte drives to create a mirror set from scratch, then I copied over all the data from the precious single drive. Cheap mass storage is the gift that just keeps on giving.

I'm an instinctive data hoarder, I guess, and always backup important data six ways from Sunday. For the university, I set up this gigantic network of backup computers, two in the Amazon cloud, three more at three different external hosting companies, and my office machines, all backing up each other, some data sets as often as once per hour. The HabitableZone database and several others are on an hourly schedule. My most critical data gets backed up literally six ways, and seven times more often than just Sunday.

I can relate.