Having a Disaster Recovery Plan (DRP) is essential for any business-critical application. This document provides guidance for designing resilient workloads on AWS, including how to define recovery objectives, recommended recovery strategies for core architecture components, and how to ensure the DRP is clearly defined and well-tested.
Establishing RTO and RPO Targets
Recovery Time Objective (RTO):
The maximum acceptable time to restore a workload after an outage.
Recovery Point Objective (RPO):
The maximum acceptable amount of data loss, measured in time.
Steps to Establish RTO and RPO:
1. Business Impact Analysis
- Identify constraints such as service level agreements (SLA) and external compliance requirements.
- Evaluate the impact of downtime and/or data loss.
- Engage stakeholders to determine acceptable downtime and data loss.
- Balance the cost of achieving a low RTO/RPO with the criticality of the application.
2. Define RTO/RPO for the application
Typical RTO/RPO based on application criticality:
- Mission-critical (Tier-1): RTO ≤ 15 minutes, RPO near-zero.
- Tier-2: RTO ≤ 4 hours, RPO ≤ 2 hours.
- Tier-3: RTO 8-24 hours, RPO ≤ 4 hours.
3. Document & Review
- Record RTO and RPO targets in an Architecture Decision Record (ADR).
- Review targets annually, or whenever there are significant changes in workload or business requirements.
Recovery Process for Core Architecture Components
To ensure rapid recovery, automation, observability, and infrastructure as code (IaC) are recommended strategies.
Component
Recovery Strategy
Compute (EC2, ECS, Lambda)
Use Auto Scaling Groups (ASGs), backups, and IaC
Databases (RDS, DynamoDB, Aurora)
Enable backups with point-in-time recovery, Multi-AZ, and cross-region replication
Storage (S3, EBS, EFS, FSx)
Enable versioning (S3), backups, and cross-region replication
Infrastructure (CloudFormation/Terraform)
Store templates/code in version-controlled repositories
Recovery Workflow:
1. Failure Detection
Use CloudWatch alarms, AWS Health Dashboard, and custom monitoring solutions.
2. Notification and Escalation
Integrate alerts with AWS SNS, PagerDuty, or Slack for immediate visibility.
3. Automated Failover
Use Route 53 failover routing, Lambda for automation, and Auto Scaling.
4. Infrastructure Restoration
Deploy infrastructure using IaC tools (e.g., CloudFormation, Terraform).
5. Data Restoration
Restore from snapshots, backups, or use cross-region recovery mechanisms as needed.
6. Validation
Conduct smoke testing or automated validation checks to confirm recovery success.
7. Post-Recovery Review
Perform root cause analysis (RCA) and update runbooks accordingly.
Documentation and Testing
Effective communication ensures that customers are informed and confident in the service’s resilience.
- Documentation and Transparency:
- Provide an overview of resilience architecture in customer-facing documentation or onboarding materials.
- Share RTO/RPO targets and demonstrate alignment with customer expectations.
- Maintain detailed runbooks covering recovery procedures for different scenarios.
2. SLAs and Contracts:
- Ensure that Service Level Agreements (SLAs) reflect realistic recovery commitments.
- Align SLAs with the AWS Shared Responsibility Model and clarify roles and responsibilities.
3. Resilience Testing Reports
- Conduct regular DR tests simulating various failure scenarios.
- Document recovery times and identify areas for improvement.
- Update runbooks and automate recovery processes wherever possible.
4. Incident Communication Plan
- Define communication channels (e.g., status pages, email, support tickets).
- Prepare and use pre-approved templates for incident updates to ensure consistency and speed.
Poorly planned disaster recovery can turn minor outages into major business disruptions. But with clearly defined RTO/RPO targets, automated recovery workflows, and a culture of regular resilience testing, Cloud architectures can withstand failure and recover predictably, quickly, and securely.
Our AWS Well-Architected Framework (WAF) reviews place a strong emphasis on resilience and operational excellence – two areas essential for safeguarding mission-critical workloads. As an AWS Advanced Tier Partner, we can also help unlock AWS funding programmes to subsidise your review, making it easier to identify risks, strengthen recovery processes, and build customer trust before an incident ever occurs.
To set up a free AWS WAF consultation with us, visit our information page, or check out our AWS Marketplace listing below.
