AWS Elastic Disaster Recovery

aws/migration aws/dr aws/service

💡 Definition

AWS Elastic Disaster Recovery (DRS) is a highly resilient and cost-effective disaster recovery service that minimizes downtime and data loss with fast, reliable recovery of on-premises and cloud-based applications to AWS. It continuously replicates your servers to a low-cost staging area in your target AWS Region.

🔑 Key Concepts

Continuous Replication: Continuously replicates data from your source servers (on-premises or other clouds) to a low-cost staging area in your AWS account. This minimizes data loss (RPO - Recovery Point Objective).
Low RTO/RPO: Designed for a low Recovery Time Objective (RTO) and Recovery Point Objective (RPO) for critical applications.
Automated Conversion: During a drill or recovery, DRS automatically converts your source servers to run on AWS EC2 instances.
Cost-Effective Staging: Uses a minimal, low-cost staging area (e.g., small EC2 instance with EBS replication) to keep DR costs down.
Non-Disruptive Testing: Allows for non-disruptive disaster recovery drills and testing.

⚙️ How it Works

You install a lightweight replication agent on your source servers. This agent continuously replicates data to a low-cost staging area in your chosen AWS Region. In the event of a disaster, you initiate a recovery. DRS then launches fully provisioned EC2 instances in your target AWS account, using the replicated data, and automatically converts the servers to be native to AWS.

🎯 Use Cases

Disaster Recovery for Critical Applications: Protecting mission-critical applications that require minimal downtime and data loss.
On-Premises to AWS DR: Establishing a reliable DR solution for your on-premises data centers in AWS.
Cross-Cloud DR: Replicating applications from other cloud providers to AWS for DR.
Data Center Migration (Mass Migration): While primarily DR, it can be used for rapid rehosting migrations.

💰 Pricing Model

Per Server: Charged per source server replicated per hour.
Underlying AWS Resources: You also pay for the AWS resources used in the staging area (e.g., small EC2 instance, EBS storage) and for the target EC2 instances launched during recovery or drills.

📝 Exam Tips (CLF-C02)

Keywords: "Disaster recovery", "Continuous replication", "Minimize downtime/data loss", "On-premises to AWS", "Low RTO/RPO".
Understand that DRS is for application-level disaster recovery, converting source servers to run natively on EC2 during recovery.
Complements Backup by providing a full system recovery solution with lower RTO/RPO.

See Also: * EC2 * Backup * DMS * AWS Migration Hub * Business Continuity Plan(BCP)