OK, back on topic....

There's some good advice in this thread, but there's one important distinction to make with backups and mirroring I haven't seen here yet.

There are two distinct reasons to back up your data.

One is hardware failure. That's the hard drive or controller crashing, spilling a beverage on the system and frying it, etc.

The other is a soft error, what I call pilot error. That's where you accidentally delete a necessary file, install some software that wreaks havoc on your files, etc. It's not always a user problem, but IME it most often is.

In the first scenario, mirroring does a good job. A hard drive fries, the system breaks the mirror and carries on business on the second drive, giving the user time to switch out the first drive. Of course if someone spills a beverage over the whole system, or both drives are tied to a single controller that goes bonkers, then there's a problem.

Which is where the second solution comes in--backing up the files themselves. I'm a contrarian in that I don't recommend disk image software, as I find that it's too easy to end up with a corrupted disk image. Instead I back up certain directories (projects, samples, vsts, presets, etc), and selectively restore. This has saved my bacon a number of times where an individual file or two in the backup is corrupt, and I'm able to restore everything else and grab those two files from an earlier backup.

 If the entire system is unstable, I'll do a Windows system restore, or more likely just reinstall Windows and Sonar, then selectively restore  content.