disaster-recovery-plan

## Purpose Produce a disaster recovery (DR) and business continuity plan that defines, per system, how much downtime (RTO) and data loss (RPO) is tolerable, and the concrete backup, replication, and failover procedure required to stay within those limits when the primary environment is lost entirely. **A backup that has never been restored is not a backup - it is an unverified assumption.** This skill treats the recovery drill, not the document, as the real proof the plan works. ## Input **Works best with:** The name of the system or service, and what infrastructure it currently runs on. **Also valuable:** Current backup tooling and frequency, any prior outage or data-loss history, compliance obligations (PCI-DSS, SOC 2), and the business cost of downtime or data loss for this system. **Example invocation:** `Write a DR plan for our production system. We run on a single VPS with MySQL, daily automated backups to object storage, no secondary region, and no replica database. Extended downtime and data loss are both expensive for us, but we've never tested a full restore.` ## Key Concepts ### RTO vs RPO - **RTO (Recovery Time Objective):** The maximum acceptable time the system can be down before the business impact becomes unacceptable. Answers "how long can we be down?" - **RPO (Recovery Point Objective):** The maximum acceptable amount of data loss, measured in time. Answers "how much data can we afford to lose?" An RPO of 1 hour means backups/replication must run at l...