I suggest using RAID (level 1 or higher) for data security, and be careful with backups as they can themselves become an additional point of failure if they fall in the wrong hands.
RAID may be used for security via virtual disk encryption but its purpose is regarding performance, fault tolerance and redundancy thru multiple drives and schemes - beside other specifics.
Whilst RAID 1 offers only mirroring - thus achieving primary purpose - if performance is not requirement, RAID 5/6 is far more fault tolerant due to its distributed parity mechanism. If performance is a requirement, RAID 50/60 can be used which adds additional drives for performance reasons. In both cases, hot spare drives are advised, so in case of fault, the RAID array can be promptly recreated.
RAID 10 is quite basic and not quite fault tolerant so should not be used for any even remotely sensitive storage. RAID 0 - stripping - is a fool's friend.
Ofc, hardware RAID modules should be preferred wherever possible as RAID O/S implementation may lead to serious data loss.