One of the most common comments/questions i get when I’m speaking or meeting with people is “I have a Drobo / RAID / mirrored drive does this mean my data is backed up?”  The answer to that question is usually no.

A mirrored or RAID drive (a Drobo is a RAID drive) keeps your data safe from hardware failure but if that is the only location your data is stored on, then no it is not backed up.  A backup is a separate copy of your data on a different physical device.

Mirror and Raid devices when used as the primary location for storage are great in case of drive failure. You can still keep working on the remaining drive(s). But if you accidentally delete a file or suffer a disaster then all your data will be gone from the one device.

You must have at least two and preferably three copies of your data with one of these copies being a physical distance away from the first two copies. If a disaster such as fire or flood destroys your first two copies you can still access your third copy off site.

I actually use a NAS with mirrored drives for my on site backup and I find it a great model. I just make sure data is backed up elsewhere.