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AWS Solutions Architect Associate (SAA-C02)

Disaster Recovery

  • Any event that has a negative impact on a company’s business continuity or finances is a disaster
  • Recovery Point Objective (RPO): how often you backup your data (determines how much data are you willing to lose in case of a disaster)
  • Recovery Time Objective (RTO): how long it takes to recover from the disaster (down time)
  • Diagram
    • attachments/Pasted image 20220513102636.jpg

Strategies

Backup & Restore

  • High RPO (hours)
  • Need to spin up instances and restore volumes from snapshots in case of disaster => High RTO
  • Cheapest & easiest to manage

Pilot Light

  • Critical parts of the app are always running in the cloud (eg. continuous replication of data to another region)
  • Low RPO (minutes)
  • Critical systems are already up => Low RTO
  • Ideal when RPO should be in minutes and the solution should be inexpensive
  • DB is critical so it is replicated continuously but EC2 instance is spin up only when a disaster strikes

Warm Standby

  • A complete backup system is up and running at the minimum capacity. This system is quickly scaled to production capacity in case of a disaster.
  • Very low RPO & RTO (minutes)
  • Expensive

Multi-Site or Hot Site Approach

  • A backup system is running at full production capacity and the request can be routed to either the main or the backup system.
  • Multi-data center approach
  • Lowest RPO & RTO (minutes or seconds)
  • Very Expensive

Last updated: 2022-05-18