Also, “San disk” is very different, linguistically, from “SanDisk”. Would you buy a set of dining room furniture from a brand called Notable? That’s a bit different from No table, isn’t it?
Ref: https://www.snopes.com/fact-check/chevrolet-nova-name-spanish/
RAID is redundancy, not backup. The main purpose is to keep your system available while you deal with certain, specific types of failures. Also, for all intents and purposes, RAID2 isn’t a thing. I suspect you were reading about RAIDZ, RAID using ZFS. While it has proponents and advantages, it won’t secure your data any more than the common RAID5/6.
Backup is to make sure you don’t lose data, regardless of what happened. This includes hardware failures, user error, bad/malicious software, and more.
If your data is important to you, setup a backup. If you need 100% uptime, setup a backup, then setup RAID.