“Configuration drift” is a common term in data center operations. It basically refers to when the data center’s production or data hosting infrastructure become different from their back-up and recovery configurations. Businesses configure identical backups for disaster recovery purposes.
So, if you’re running production servers through the long-term, you might end-up altering it through manual, ad-hoc configuration changes.
In the short-run, the changes might appear sensible, but in time, you’re putting your servers at risk of breaking compatibility between your production and back-up environments.