Backups you have actually restored

Every backup system I have ever set up worked perfectly until the first time I needed it. The difference between the ones that saved me and the ones that did not was never the tool.

The routine

Once a quarter, restore into a scratch directory and diff. Not the whole thing, if the whole thing is large: the newest file, the oldest file, and one chosen at random. Ten minutes.

Write down the date you did it. If the last date is more than two quarters old, you do not have backups, you have a cron job.