Simply running RAID (short for Redundant Array of Inexpensive Disks) on your desktop system is not backup. A backup is a separate copy, stored on a separate system, and ideally you have another copy offsite. You can follow the line of disaster: If your main system explodes, you have a backup on your spare system; if that system explodes, you have a copy on your main system; but if your home explodes, you have a copy offsite. That’s enough exploding.
What RAID is great for is redundancy, and as we all know, redundant systems are there to increase system reliability through duplication of functions.
In the case of RAID 1, 5, and 6, an entire drive can fail, and the parity (or mirror) the system uses can enable it to…