Words to live by.
Remember: Data you don't have at least two copies of is data you don't care about.
Just because you have the files on a RAID-1 NAS, that doesn't mean you have backup. RAID of any level is not backup, it's just hardware fault protection, a performance boost, or both. However, it's not backup of any kind! If you don't have the file anywhere else, you have one copy , no matter what RAID level you run.