Test your backups

These docs frequently admonish you to "TEST YOUR BACKUPS".  Here are discussed a few methods, concrete suggestsions which may help you decide how well-tested your backups are.


The DR exercise

Pick a machine which is important to you.  Install (or clone?) a new, bare system image with the system and application software relevant to its function.  Restore the application data, and attempt to make the new box function.

Expect this process to have speed bumps;  you will have manifold opportunities to update your installation and maintenance documentation. 


Restore ALL the things

For some important machine, restore all the data which you think is relevant to its function. This process has a liability:  If you've failed to capture some aspect of the service's function, you won't discover it.   


Restore something

Pick a machine, and then pick an interesting file.  "Interesting" here means some file which is not trivially replicable from some other source.  System files are probably out, but system configuration files are likely interesting.  Restore it, and make sure its contents are what you think should be there.

This spot-checking doesn't have the exhaustive completeness of the DR exercise, but it can be done simply and without a great investment of time.   So long as you don't test the same file every time, you will eventually end up with a very good sense of how well you've covered the important aspects of your operation.