A backup job that completes without error and a backup you can actually restore from are not the same thing. We've seen backup software report success for months while the underlying restore path was quietly broken — a permissions change, a corrupted catalog, a retention policy that silently stopped capturing a critical database. The only way to know your backup actually works is to restore from it, on a schedule, before you need it for real.
What a real DR test looks like
A proper test isn't checking a box that says the job ran. It means picking a system — ideally rotating through your critical systems on a schedule rather than always testing the easy one — and actually restoring it to an isolated environment. For file-level backups, that means confirming the files open and are current. For full-VM or database backups, it means actually booting the restored system and validating it functions, not just that the restore process completed.
The quarterly cadence we run
We test on a quarterly rotation: each quarter, one critical system gets a full restore test to an isolated environment, with results logged — what worked, what didn't, how long it took. Annually, we run a broader test that exercises the full DR failover process end to end, not just a single system restore. This cadence catches configuration drift before it becomes a crisis, since infrastructure changes constantly and a DR plan that isn't re-tested after those changes quietly stops matching the environment it's supposed to protect.
What to do when a test fails
A failed test is a good outcome, not a bad one — it means you found the gap during a scheduled drill instead of during a real outage. The response is the same either way: document exactly what broke, fix the underlying cause (not just the symptom), and re-test before considering it resolved. A backup strategy that's never failed a test hasn't necessarily been tested rigorously enough.