State is the Enemy
The traditional disaster recovery plan involves restoring from a snapshot. In a best-case scenario, this takes minutes. In a worst-case scenario, hours. The alternative is to treat infrastructure as ephemeral and push state out to distributed, strictly consistent logs, so that no single machine holds anything worth recovering.
When a node fails, it is replaced rather than repaired. Mean Time to Recovery stops being a function of how fast a backup restores and becomes a function of how fast a machine boots — which is the difference between minutes and hours.
Ephemeral Infrastructure
Immutable infrastructure is what makes that possible. Every server image is built, tested and hardened in the pipeline; once deployed, nobody logs into it. Configuration drift becomes impossible because runtime configuration changes are simply not permitted — the constraint is the feature.
A configuration change means updating code, rebuilding the image and rolling it out blue/green. The discipline forces full automation, and recovery stops being a separate procedure that gets tested once a year — it becomes a side effect of the deployment process you already run daily.