AWS Elastic Disaster Recovery
Disaster recovery for servers
Continuous block-level replication from source servers (on-prem, other clouds or EC2) to a low-cost staging area on AWS; when an incident occurs, it launches recovery servers within minutes (RPO measured in seconds).
- Cost$$ Medium
- Difficulty●●●●●
- Costs money when idle?Yes
- Managed by AWS
- In examsSAA · SOA
Think of it asLike a backup office whose files are updated every second: just flip on the lights and you can get to work.
When to use it
✓ Use it when
You need DR for servers with low RPO/RTO without maintaining a full standby infrastructure running.
✗ Avoid it when
You only need periodic backups → Backup; moving servers to AWS permanently in one go → Application Migration Service.
Common uses
- DR for on-prem data centers to AWS
- DR between two AWS Regions
- Recovery drills without affecting production systems
What does it cost?
- Pricing model: Hourly fee per replicated source server, plus staging EC2/EBS, snapshots, and resources during drills or recovery.
⚠️ Cost traps
Forgetting to shut down recovery drill instances.
Related services
SAA-C03 study guide
DRS is covered in these study modules: