Also called: disaster recovery drill, failover test, game day
In plain English
A DR drill is a deliberate rehearsal of your disaster-recovery procedure — typically a planned switchover or a restore-and-promote in the DR region — run while everything is healthy, to prove the plan works and to measure your real RPO and RTO.
Why it matters
An untested DR plan has an unknown RTO. Drills surface the gaps that only appear under a real role change — stale connection strings, missing roles, slow detection — before an actual disaster forces you to discover them the hard way.